1 |
1275 |
phoenix |
/proc/sys/net/ipv4/* Variables:
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2 |
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3 |
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ip_forward - BOOLEAN
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4 |
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5 |
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not 0 - enabled
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6 |
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7 |
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Forward Packets between interfaces.
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8 |
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9 |
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This variable is special, its change resets all configuration
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10 |
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parameters to their default state (RFC1122 for hosts, RFC1812
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11 |
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for routers)
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12 |
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13 |
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ip_default_ttl - INTEGER
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14 |
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default 64
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15 |
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16 |
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ip_no_pmtu_disc - BOOLEAN
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17 |
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Disable Path MTU Discovery.
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18 |
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default FALSE
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19 |
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20 |
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IP Fragmentation:
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21 |
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22 |
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ipfrag_high_thresh - INTEGER
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23 |
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Maximum memory used to reassemble IP fragments. When
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24 |
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ipfrag_high_thresh bytes of memory is allocated for this purpose,
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25 |
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the fragment handler will toss packets until ipfrag_low_thresh
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26 |
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is reached.
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27 |
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28 |
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ipfrag_low_thresh - INTEGER
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29 |
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See ipfrag_high_thresh
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30 |
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31 |
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ipfrag_time - INTEGER
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32 |
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Time in seconds to keep an IP fragment in memory.
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33 |
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34 |
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INET peer storage:
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35 |
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36 |
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inet_peer_threshold - INTEGER
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37 |
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The approximate size of the storage. Starting from this threshold
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38 |
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entries will be thrown aggressively. This threshold also determines
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39 |
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entries' time-to-live and time intervals between garbage collection
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40 |
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passes. More entries, less time-to-live, less GC interval.
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41 |
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42 |
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inet_peer_minttl - INTEGER
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43 |
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Minimum time-to-live of entries. Should be enough to cover fragment
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44 |
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time-to-live on the reassembling side. This minimum time-to-live is
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45 |
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guaranteed if the pool size is less than inet_peer_threshold.
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46 |
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Measured in jiffies(1).
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47 |
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48 |
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inet_peer_maxttl - INTEGER
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49 |
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Maximum time-to-live of entries. Unused entries will expire after
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50 |
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this period of time if there is no memory pressure on the pool (i.e.
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51 |
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when the number of entries in the pool is very small).
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52 |
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Measured in jiffies(1).
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53 |
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54 |
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inet_peer_gc_mintime - INTEGER
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55 |
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Minimum interval between garbage collection passes. This interval is
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56 |
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in effect under high memory pressure on the pool.
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57 |
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Measured in jiffies(1).
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58 |
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59 |
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inet_peer_gc_maxtime - INTEGER
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60 |
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Minimum interval between garbage collection passes. This interval is
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61 |
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in effect under low (or absent) memory pressure on the pool.
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62 |
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Measured in jiffies(1).
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63 |
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64 |
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TCP variables:
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65 |
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66 |
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tcp_syn_retries - INTEGER
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67 |
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Number of times initial SYNs for an active TCP connection attempt
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68 |
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will be retransmitted. Should not be higher than 255. Default value
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69 |
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is 5, which corresponds to ~180seconds.
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70 |
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71 |
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tcp_synack_retries - INTEGER
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72 |
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Number of times SYNACKs for a passive TCP connection attempt will
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73 |
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be retransmitted. Should not be higher than 255. Default value
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74 |
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is 5, which corresponds to ~180seconds.
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75 |
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76 |
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tcp_keepalive_time - INTEGER
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77 |
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How often TCP sends out keepalive messages when keepalive is enabled.
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78 |
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Default: 2hours.
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79 |
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80 |
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tcp_keepalive_probes - INTEGER
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81 |
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How many keepalive probes TCP sends out, until it decides that the
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82 |
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connection is broken. Default value: 9.
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83 |
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84 |
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tcp_keepalive_intvl - INTEGER
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85 |
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How frequently the probes are send out. Multiplied by
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86 |
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tcp_keepalive_probes it is time to kill not responding connection,
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87 |
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after probes started. Default value: 75sec i.e. connection
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88 |
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will be aborted after ~11 minutes of retries.
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89 |
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90 |
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tcp_retries1 - INTEGER
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91 |
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How many times to retry before deciding that something is wrong
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92 |
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and it is necessary to report this suspection to network layer.
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93 |
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Minimal RFC value is 3, it is default, which corresponds
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94 |
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to ~3sec-8min depending on RTO.
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95 |
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96 |
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tcp_retries2 - INTEGER
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97 |
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How may times to retry before killing alive TCP connection.
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98 |
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RFC1122 says that the limit should be longer than 100 sec.
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99 |
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It is too small number. Default value 15 corresponds to ~13-30min
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100 |
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depending on RTO.
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101 |
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102 |
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tcp_orphan_retries - INTEGER
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103 |
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How may times to retry before killing TCP connection, closed
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104 |
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by our side. Default value 7 corresponds to ~50sec-16min
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105 |
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depending on RTO. If you machine is loaded WEB server,
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106 |
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you should think about lowering this value, such sockets
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107 |
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may consume significant resources. Cf. tcp_max_orphans.
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108 |
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109 |
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tcp_fin_timeout - INTEGER
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110 |
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Time to hold socket in state FIN-WAIT-2, if it was closed
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111 |
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by our side. Peer can be broken and never close its side,
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112 |
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or even died unexpectedly. Default value is 60sec.
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113 |
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Usual value used in 2.2 was 180 seconds, you may restore
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114 |
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it, but remember that if your machine is even underloaded WEB server,
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115 |
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you risk to overflow memory with kilotons of dead sockets,
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116 |
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FIN-WAIT-2 sockets are less dangerous than FIN-WAIT-1,
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117 |
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because they eat maximum 1.5K of memory, but they tend
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118 |
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to live longer. Cf. tcp_max_orphans.
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119 |
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120 |
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tcp_max_tw_buckets - INTEGER
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121 |
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Maximal number of timewait sockets held by system simultaneously.
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122 |
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If this number is exceeded time-wait socket is immediately destroyed
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123 |
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and warning is printed. This limit exists only to prevent
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124 |
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simple DoS attacks, you _must_ not lower the limit artificially,
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125 |
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but rather increase it (probably, after increasing installed memory),
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126 |
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if network conditions require more than default value.
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127 |
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128 |
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tcp_tw_recycle - BOOLEAN
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129 |
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Enable fast recycling TIME-WAIT sockets. Default value is 0.
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130 |
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It should not be changed without advice/request of technical
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131 |
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experts.
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132 |
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133 |
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tcp_tw_reuse - BOOLEAN
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134 |
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Allow to reuse TIME-WAIT sockets for new connections when it is
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135 |
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safe from protocol viewpoint. Default value is 0.
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136 |
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It should not be changed without advice/request of technical
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137 |
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experts.
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138 |
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|
139 |
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tcp_max_orphans - INTEGER
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140 |
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Maximal number of TCP sockets not attached to any user file handle,
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141 |
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held by system. If this number is exceeded orphaned connections are
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142 |
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reset immediately and warning is printed. This limit exists
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143 |
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only to prevent simple DoS attacks, you _must_ not rely on this
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144 |
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or lower the limit artificially, but rather increase it
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145 |
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(probably, after increasing installed memory),
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146 |
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if network conditions require more than default value,
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147 |
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and tune network services to linger and kill such states
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148 |
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more aggressively. Let me to remind again: each orphan eats
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149 |
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up to ~64K of unswappable memory.
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150 |
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151 |
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tcp_abort_on_overflow - BOOLEAN
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152 |
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If listening service is too slow to accept new connections,
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153 |
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reset them. Default state is FALSE. It means that if overflow
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154 |
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occurred due to a burst, connection will recover. Enable this
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155 |
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option _only_ if you are really sure that listening daemon
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156 |
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cannot be tuned to accept connections faster. Enabling this
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157 |
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option can harm clients of your server.
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158 |
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159 |
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tcp_syncookies - BOOLEAN
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160 |
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Only valid when the kernel was compiled with CONFIG_SYNCOOKIES
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161 |
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Send out syncookies when the syn backlog queue of a socket
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162 |
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overflows. This is to prevent against the common 'syn flood attack'
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163 |
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Default: FALSE
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164 |
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165 |
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Note, that syncookies is fallback facility.
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166 |
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It MUST NOT be used to help highly loaded servers to stand
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167 |
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against legal connection rate. If you see synflood warnings
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168 |
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in your logs, but investigation shows that they occur
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169 |
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because of overload with legal connections, you should tune
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170 |
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another parameters until this warning disappear.
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171 |
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See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow.
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172 |
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173 |
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syncookies seriously violate TCP protocol, do not allow
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174 |
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to use TCP extensions, can result in serious degradation
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175 |
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of some services (f.e. SMTP relaying), visible not by you,
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176 |
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but your clients and relays, contacting you. While you see
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177 |
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synflood warnings in logs not being really flooded, your server
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178 |
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is seriously misconfigured.
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179 |
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|
180 |
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tcp_stdurg - BOOLEAN
|
181 |
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Use the Host requirements interpretation of the TCP urg pointer field.
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182 |
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Most hosts use the older BSD interpretation, so if you turn this on
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183 |
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Linux might not communicate correctly with them.
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184 |
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Default: FALSE
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185 |
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|
186 |
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tcp_max_syn_backlog - INTEGER
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187 |
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Maximal number of remembered connection requests, which are
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188 |
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still did not receive an acknowledgement from connecting client.
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189 |
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Default value is 1024 for systems with more than 128Mb of memory,
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190 |
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and 128 for low memory machines. If server suffers of overload,
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191 |
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try to increase this number.
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192 |
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193 |
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tcp_window_scaling - BOOLEAN
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194 |
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Enable window scaling as defined in RFC1323.
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195 |
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196 |
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tcp_timestamps - BOOLEAN
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197 |
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Enable timestamps as defined in RFC1323.
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198 |
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199 |
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tcp_sack - BOOLEAN
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200 |
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Enable select acknowledgments (SACKS).
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201 |
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202 |
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tcp_fack - BOOLEAN
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203 |
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Enable FACK congestion avoidance and fast restransmission.
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204 |
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The value is not used, if tcp_sack is not enabled.
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205 |
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206 |
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tcp_dsack - BOOLEAN
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207 |
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Allows TCP to send "duplicate" SACKs.
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208 |
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209 |
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tcp_ecn - BOOLEAN
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210 |
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Enable Explicit Congestion Notification in TCP.
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211 |
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212 |
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tcp_reordering - INTEGER
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213 |
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Maximal reordering of packets in a TCP stream.
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214 |
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Default: 3
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215 |
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216 |
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tcp_retrans_collapse - BOOLEAN
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217 |
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Bug-to-bug compatibility with some broken printers.
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218 |
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On retransmit try to send bigger packets to work around bugs in
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219 |
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certain TCP stacks.
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220 |
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|
221 |
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tcp_wmem - vector of 3 INTEGERs: min, default, max
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222 |
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min: Amount of memory reserved for send buffers for TCP socket.
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223 |
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Each TCP socket has rights to use it due to fact of its birth.
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224 |
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Default: 4K
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225 |
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226 |
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default: Amount of memory allowed for send buffers for TCP socket
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227 |
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by default. This value overrides net.core.wmem_default used
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228 |
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by other protocols, it is usually lower than net.core.wmem_default.
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229 |
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Default: 16K
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230 |
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231 |
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max: Maximal amount of memory allowed for automatically selected
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232 |
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send buffers for TCP socket. This value does not override
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233 |
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net.core.wmem_max, "static" selection via SO_SNDBUF does not use this.
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234 |
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Default: 128K
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235 |
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236 |
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tcp_rmem - vector of 3 INTEGERs: min, default, max
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237 |
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min: Minimal size of receive buffer used by TCP sockets.
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238 |
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It is guaranteed to each TCP socket, even under moderate memory
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239 |
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pressure.
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240 |
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Default: 8K
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241 |
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242 |
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default: default size of receive buffer used by TCP sockets.
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243 |
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This value overrides net.core.rmem_default used by other protocols.
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244 |
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Default: 87380 bytes. This value results in window of 65535 with
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245 |
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default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit
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246 |
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less for default tcp_app_win. See below about these variables.
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247 |
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248 |
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max: maximal size of receive buffer allowed for automatically
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249 |
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selected receiver buffers for TCP socket. This value does not override
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250 |
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net.core.rmem_max, "static" selection via SO_RCVBUF does not use this.
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251 |
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Default: 87380*2 bytes.
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252 |
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253 |
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tcp_mem - vector of 3 INTEGERs: min, pressure, max
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254 |
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low: below this number of pages TCP is not bothered about its
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255 |
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memory appetite.
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256 |
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257 |
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pressure: when amount of memory allocated by TCP exceeds this number
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258 |
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of pages, TCP moderates its memory consumption and enters memory
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259 |
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pressure mode, which is exited when memory consumtion falls
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260 |
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under "low".
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261 |
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262 |
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high: number of pages allowed for queueing by all TCP sockets.
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263 |
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|
264 |
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Defaults are calculated at boot time from amount of available
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265 |
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memory.
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266 |
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|
267 |
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tcp_app_win - INTEGER
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268 |
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Reserve max(window/2^tcp_app_win, mss) of window for application
|
269 |
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buffer. Value 0 is special, it means that nothing is reserved.
|
270 |
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Default: 31
|
271 |
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|
272 |
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tcp_adv_win_scale - INTEGER
|
273 |
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Count buffering overhead as bytes/2^tcp_adv_win_scale
|
274 |
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(if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale),
|
275 |
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if it is <= 0.
|
276 |
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Default: 2
|
277 |
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|
278 |
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tcp_rfc1337 - BOOLEAN
|
279 |
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If set, the TCP stack behaves conforming to RFC1337. If unset,
|
280 |
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we are not conforming to RFC, but prevent TCP TIME_WAIT
|
281 |
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asassination.
|
282 |
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Default: 0
|
283 |
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|
284 |
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tcp_low_latency - BOOLEAN
|
285 |
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If set, the TCP stack makes decisions that prefer lower
|
286 |
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latency as opposed to higher throughput. By default, this
|
287 |
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option is not set meaning that higher throughput is preferred.
|
288 |
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An example of an application where this default should be
|
289 |
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changed would be a Beowulf compute cluster.
|
290 |
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Default: 0
|
291 |
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|
292 |
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ip_local_port_range - 2 INTEGERS
|
293 |
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Defines the local port range that is used by TCP and UDP to
|
294 |
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choose the local port. The first number is the first, the
|
295 |
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second the last local port number. Default value depends on
|
296 |
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amount of memory available on the system:
|
297 |
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> 128Mb 32768-61000
|
298 |
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< 128Mb 1024-4999 or even less.
|
299 |
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This number defines number of active connections, which this
|
300 |
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system can issue simultaneously to systems not supporting
|
301 |
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TCP extensions (timestamps). With tcp_tw_recycle enabled
|
302 |
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(i.e. by default) range 1024-4999 is enough to issue up to
|
303 |
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2000 connections per second to systems supporting timestamps.
|
304 |
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|
305 |
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ip_nonlocal_bind - BOOLEAN
|
306 |
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If set, allows processes to bind() to non-local IP adresses,
|
307 |
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which can be quite useful - but may break some applications.
|
308 |
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Default: 0
|
309 |
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|
310 |
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ip_dynaddr - BOOLEAN
|
311 |
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If set non-zero, enables support for dynamic addresses.
|
312 |
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If set to a non-zero value larger than 1, a kernel log
|
313 |
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message will be printed when dynamic address rewriting
|
314 |
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occurs.
|
315 |
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Default: 0
|
316 |
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|
317 |
|
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icmp_echo_ignore_all - BOOLEAN
|
318 |
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icmp_echo_ignore_broadcasts - BOOLEAN
|
319 |
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If either is set to true, then the kernel will ignore either all
|
320 |
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ICMP ECHO requests sent to it or just those to broadcast/multicast
|
321 |
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addresses, respectively.
|
322 |
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|
323 |
|
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icmp_ratelimit - INTEGER
|
324 |
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Limit the maximal rates for sending ICMP packets whose type matches
|
325 |
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icmp_ratemask (see below) to specific targets.
|
326 |
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|
327 |
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Default: 100
|
328 |
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|
329 |
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icmp_ratemask - INTEGER
|
330 |
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Mask made of ICMP types for which rates are being limited.
|
331 |
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Significant bits: IHGFEDCBA9876543210
|
332 |
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Default mask: 0000001100000011000 (6168)
|
333 |
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|
334 |
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Bit definitions (see include/linux/icmp.h):
|
335 |
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|
336 |
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3 Destination Unreachable *
|
337 |
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4 Source Quench *
|
338 |
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5 Redirect
|
339 |
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8 Echo Request
|
340 |
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B Time Exceeded *
|
341 |
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C Parameter Problem *
|
342 |
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D Timestamp Request
|
343 |
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E Timestamp Reply
|
344 |
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F Info Request
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345 |
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G Info Reply
|
346 |
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H Address Mask Request
|
347 |
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I Address Mask Reply
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348 |
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|
349 |
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* These are rate limited by default (see default mask above)
|
350 |
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|
351 |
|
|
icmp_ignore_bogus_error_responses - BOOLEAN
|
352 |
|
|
Some routers violate RFC1122 by sending bogus responses to broadcast
|
353 |
|
|
frames. Such violations are normally logged via a kernel warning.
|
354 |
|
|
If this is set to TRUE, the kernel will not give such warnings, which
|
355 |
|
|
will avoid log file clutter.
|
356 |
|
|
Default: FALSE
|
357 |
|
|
|
358 |
|
|
igmp_max_memberships - INTEGER
|
359 |
|
|
Change the maximum number of multicast groups we can subscribe to.
|
360 |
|
|
Default: 20
|
361 |
|
|
|
362 |
|
|
conf/interface/* changes special settings per interface (where "interface" is
|
363 |
|
|
the name of your network interface)
|
364 |
|
|
conf/all/* is special, changes the settings for all interfaces
|
365 |
|
|
|
366 |
|
|
|
367 |
|
|
log_martians - BOOLEAN
|
368 |
|
|
Log packets with impossible addresses to kernel log.
|
369 |
|
|
log_martians for the interface will be enabled if at least one of
|
370 |
|
|
conf/{all,interface}/log_martians is set to TRUE,
|
371 |
|
|
it will be disabled otherwise
|
372 |
|
|
|
373 |
|
|
accept_redirects - BOOLEAN
|
374 |
|
|
Accept ICMP redirect messages.
|
375 |
|
|
accept_redirects for the interface will be enabled if:
|
376 |
|
|
- both conf/{all,interface}/accept_redirects are TRUE in the case forwarding
|
377 |
|
|
for the interface is enabled
|
378 |
|
|
or
|
379 |
|
|
- at least one of conf/{all,interface}/accept_redirects is TRUE in the case
|
380 |
|
|
forwarding for the interface is disabled
|
381 |
|
|
accept_redirects for the interface will be disabled otherwise
|
382 |
|
|
default TRUE (host)
|
383 |
|
|
FALSE (router)
|
384 |
|
|
|
385 |
|
|
forwarding - BOOLEAN
|
386 |
|
|
Enable IP forwarding on this interface.
|
387 |
|
|
|
388 |
|
|
mc_forwarding - BOOLEAN
|
389 |
|
|
Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
|
390 |
|
|
and a multicast routing daemon is required.
|
391 |
|
|
conf/all/mc_forwarding must also be set to TRUE to enable multicast routing
|
392 |
|
|
for the interface
|
393 |
|
|
|
394 |
|
|
medium_id - INTEGER
|
395 |
|
|
Integer value used to differentiate the devices by the medium they
|
396 |
|
|
are attached to. Two devices can have different id values when
|
397 |
|
|
the broadcast packets are received only on one of them.
|
398 |
|
|
The default value 0 means that the device is the only interface
|
399 |
|
|
to its medium, value of -1 means that medium is not known.
|
400 |
|
|
|
401 |
|
|
Currently, it is used to change the proxy_arp behavior:
|
402 |
|
|
the proxy_arp feature is enabled for packets forwarded between
|
403 |
|
|
two devices attached to different media.
|
404 |
|
|
|
405 |
|
|
proxy_arp - BOOLEAN
|
406 |
|
|
Do proxy arp.
|
407 |
|
|
proxy_arp for the interface will be enabled if at least one of
|
408 |
|
|
conf/{all,interface}/proxy_arp is set to TRUE,
|
409 |
|
|
it will be disabled otherwise
|
410 |
|
|
|
411 |
|
|
shared_media - BOOLEAN
|
412 |
|
|
Send(router) or accept(host) RFC1620 shared media redirects.
|
413 |
|
|
Overrides ip_secure_redirects.
|
414 |
|
|
shared_media for the interface will be enabled if at least one of
|
415 |
|
|
conf/{all,interface}/shared_media is set to TRUE,
|
416 |
|
|
it will be disabled otherwise
|
417 |
|
|
default TRUE
|
418 |
|
|
|
419 |
|
|
secure_redirects - BOOLEAN
|
420 |
|
|
Accept ICMP redirect messages only for gateways,
|
421 |
|
|
listed in default gateway list.
|
422 |
|
|
secure_redirects for the interface will be enabled if at least one of
|
423 |
|
|
conf/{all,interface}/secure_redirects is set to TRUE,
|
424 |
|
|
it will be disabled otherwise
|
425 |
|
|
default TRUE
|
426 |
|
|
|
427 |
|
|
send_redirects - BOOLEAN
|
428 |
|
|
Send redirects, if router.
|
429 |
|
|
send_redirects for the interface will be enabled if at least one of
|
430 |
|
|
conf/{all,interface}/send_redirects is set to TRUE,
|
431 |
|
|
it will be disabled otherwise
|
432 |
|
|
Default: TRUE
|
433 |
|
|
|
434 |
|
|
bootp_relay - BOOLEAN
|
435 |
|
|
Accept packets with source address 0.b.c.d destined
|
436 |
|
|
not to this host as local ones. It is supposed, that
|
437 |
|
|
BOOTP relay daemon will catch and forward such packets.
|
438 |
|
|
conf/all/bootp_relay must also be set to TRUE to enable BOOTP relay
|
439 |
|
|
for the interface
|
440 |
|
|
default FALSE
|
441 |
|
|
Not Implemented Yet.
|
442 |
|
|
|
443 |
|
|
accept_source_route - BOOLEAN
|
444 |
|
|
Accept packets with SRR option.
|
445 |
|
|
conf/all/accept_source_route must also be set to TRUE to accept packets
|
446 |
|
|
with SRR option on the interface
|
447 |
|
|
default TRUE (router)
|
448 |
|
|
FALSE (host)
|
449 |
|
|
|
450 |
|
|
rp_filter - BOOLEAN
|
451 |
|
|
1 - do source validation by reversed path, as specified in RFC1812
|
452 |
|
|
Recommended option for single homed hosts and stub network
|
453 |
|
|
routers. Could cause troubles for complicated (not loop free)
|
454 |
|
|
networks running a slow unreliable protocol (sort of RIP),
|
455 |
|
|
or using static routes.
|
456 |
|
|
|
457 |
|
|
|
458 |
|
|
|
459 |
|
|
conf/all/rp_filter must also be set to TRUE to do source validation
|
460 |
|
|
on the interface
|
461 |
|
|
|
462 |
|
|
Default value is 0. Note that some distributions enable it
|
463 |
|
|
in startup scripts.
|
464 |
|
|
|
465 |
|
|
arp_filter - BOOLEAN
|
466 |
|
|
1 - Allows you to have multiple network interfaces on the same
|
467 |
|
|
subnet, and have the ARPs for each interface be answered
|
468 |
|
|
based on whether or not the kernel would route a packet from
|
469 |
|
|
the ARP'd IP out that interface (therefore you must use source
|
470 |
|
|
based routing for this to work). In other words it allows control
|
471 |
|
|
of which cards (usually 1) will respond to an arp request.
|
472 |
|
|
|
473 |
|
|
|
474 |
|
|
from other interfaces. This may seem wrong but it usually makes
|
475 |
|
|
sense, because it increases the chance of successful communication.
|
476 |
|
|
IP addresses are owned by the complete host on Linux, not by
|
477 |
|
|
particular interfaces. Only for more complex setups like load-
|
478 |
|
|
balancing, does this behaviour cause problems.
|
479 |
|
|
|
480 |
|
|
arp_filter for the interface will be enabled if at least one of
|
481 |
|
|
conf/{all,interface}/arp_filter is set to TRUE,
|
482 |
|
|
it will be disabled otherwise
|
483 |
|
|
|
484 |
|
|
arp_announce - INTEGER
|
485 |
|
|
Define different restriction levels for announcing the local
|
486 |
|
|
source IP address from IP packets in ARP requests sent on
|
487 |
|
|
interface:
|
488 |
|
|
|
489 |
|
|
1 - Try to avoid local addresses that are not in the target's
|
490 |
|
|
subnet for this interface. This mode is useful when target
|
491 |
|
|
hosts reachable via this interface require the source IP
|
492 |
|
|
address in ARP requests to be part of their logical network
|
493 |
|
|
configured on the receiving interface. When we generate the
|
494 |
|
|
request we will check all our subnets that include the
|
495 |
|
|
target IP and will preserve the source address if it is from
|
496 |
|
|
such subnet. If there is no such subnet we select source
|
497 |
|
|
address according to the rules for level 2.
|
498 |
|
|
2 - Always use the best local address for this target.
|
499 |
|
|
In this mode we ignore the source address in the IP packet
|
500 |
|
|
and try to select local address that we prefer for talks with
|
501 |
|
|
the target host. Such local address is selected by looking
|
502 |
|
|
for primary IP addresses on all our subnets on the outgoing
|
503 |
|
|
interface that include the target IP address. If no suitable
|
504 |
|
|
local address is found we select the first local address
|
505 |
|
|
we have on the outgoing interface or on all other interfaces,
|
506 |
|
|
with the hope we will receive reply for our request and
|
507 |
|
|
even sometimes no matter the source IP address we announce.
|
508 |
|
|
|
509 |
|
|
The max value from conf/{all,interface}/arp_announce is used.
|
510 |
|
|
|
511 |
|
|
Increasing the restriction level gives more chance for
|
512 |
|
|
receiving answer from the resolved target while decreasing
|
513 |
|
|
the level announces more valid sender's information.
|
514 |
|
|
|
515 |
|
|
arp_ignore - INTEGER
|
516 |
|
|
Define different modes for sending replies in response to
|
517 |
|
|
received ARP requests that resolve local target IP addresses:
|
518 |
|
|
|
519 |
|
|
on any interface
|
520 |
|
|
1 - reply only if the target IP address is local address
|
521 |
|
|
configured on the incoming interface
|
522 |
|
|
2 - reply only if the target IP address is local address
|
523 |
|
|
configured on the incoming interface and both with the
|
524 |
|
|
sender's IP address are part from same subnet on this interface
|
525 |
|
|
3 - do not reply for local addresses configured with scope host,
|
526 |
|
|
only resolutions for global and link addresses are replied
|
527 |
|
|
4-7 - reserved
|
528 |
|
|
8 - do not reply for all local addresses
|
529 |
|
|
|
530 |
|
|
The max value from conf/{all,interface}/arp_ignore is used
|
531 |
|
|
when ARP request is received on the {interface}
|
532 |
|
|
|
533 |
|
|
tag - INTEGER
|
534 |
|
|
Allows you to write a number, which can be used as required.
|
535 |
|
|
Default value is 0.
|
536 |
|
|
|
537 |
|
|
(1) Jiffie: internal timeunit for the kernel. On the i386 1/100s, on the
|
538 |
|
|
Alpha 1/1024s. See the HZ define in /usr/include/asm/param.h for the exact
|
539 |
|
|
value on your system.
|
540 |
|
|
|
541 |
|
|
Alexey Kuznetsov.
|
542 |
|
|
kuznet@ms2.inr.ac.ru
|
543 |
|
|
|
544 |
|
|
Updated by:
|
545 |
|
|
Andi Kleen
|
546 |
|
|
ak@muc.de
|
547 |
|
|
Nicolas Delon
|
548 |
|
|
delon.nicolas@wanadoo.fr
|
549 |
|
|
|
550 |
|
|
|
551 |
|
|
|
552 |
|
|
|
553 |
|
|
/proc/sys/net/ipv6/* Variables:
|
554 |
|
|
|
555 |
|
|
IPv6 has no global variables such as tcp_*. tcp_* settings under ipv4/ also
|
556 |
|
|
apply to IPv6 [XXX?].
|
557 |
|
|
|
558 |
|
|
bindv6only - BOOLEAN
|
559 |
|
|
Default value for IPV6_V6ONLY socket option,
|
560 |
|
|
which restricts use of the IPv6 socket to IPv6 communication
|
561 |
|
|
only.
|
562 |
|
|
TRUE: disable IPv4-mapped address feature
|
563 |
|
|
FALSE: enable IPv4-mapped address feature
|
564 |
|
|
|
565 |
|
|
Default: FALSE (as specified in RFC2553bis)
|
566 |
|
|
|
567 |
|
|
conf/default/*:
|
568 |
|
|
Change the interface-specific default settings.
|
569 |
|
|
|
570 |
|
|
|
571 |
|
|
conf/all/*:
|
572 |
|
|
Change all the interface-specific settings.
|
573 |
|
|
|
574 |
|
|
[XXX: Other special features than forwarding?]
|
575 |
|
|
|
576 |
|
|
conf/all/forwarding - BOOLEAN
|
577 |
|
|
Enable global IPv6 forwarding between all interfaces.
|
578 |
|
|
|
579 |
|
|
IPv4 and IPv6 work differently here; e.g. netfilter must be used
|
580 |
|
|
to control which interfaces may forward packets and which not.
|
581 |
|
|
|
582 |
|
|
This also sets all interfaces' Host/Router setting
|
583 |
|
|
'forwarding' to the specified value. See below for details.
|
584 |
|
|
|
585 |
|
|
This referred to as global forwarding.
|
586 |
|
|
|
587 |
|
|
conf/interface/*:
|
588 |
|
|
Change special settings per interface.
|
589 |
|
|
|
590 |
|
|
The functional behaviour for certain settings is different
|
591 |
|
|
depending on whether local forwarding is enabled or not.
|
592 |
|
|
|
593 |
|
|
accept_ra - BOOLEAN
|
594 |
|
|
Accept Router Advertisements; autoconfigure using them.
|
595 |
|
|
|
596 |
|
|
Functional default: enabled if local forwarding is disabled.
|
597 |
|
|
disabled if local forwarding is enabled.
|
598 |
|
|
|
599 |
|
|
accept_redirects - BOOLEAN
|
600 |
|
|
Accept Redirects.
|
601 |
|
|
|
602 |
|
|
Functional default: enabled if local forwarding is disabled.
|
603 |
|
|
disabled if local forwarding is enabled.
|
604 |
|
|
|
605 |
|
|
autoconf - BOOLEAN
|
606 |
|
|
Configure link-local addresses using L2 hardware addresses.
|
607 |
|
|
|
608 |
|
|
Default: TRUE
|
609 |
|
|
|
610 |
|
|
dad_transmits - INTEGER
|
611 |
|
|
The amount of Duplicate Address Detection probes to send.
|
612 |
|
|
Default: 1
|
613 |
|
|
|
614 |
|
|
forwarding - BOOLEAN
|
615 |
|
|
Configure interface-specific Host/Router behaviour.
|
616 |
|
|
|
617 |
|
|
Note: It is recommended to have the same setting on all
|
618 |
|
|
interfaces; mixed router/host scenarios are rather uncommon.
|
619 |
|
|
|
620 |
|
|
FALSE:
|
621 |
|
|
|
622 |
|
|
By default, Host behaviour is assumed. This means:
|
623 |
|
|
|
624 |
|
|
1. IsRouter flag is not set in Neighbour Advertisements.
|
625 |
|
|
2. Router Solicitations are being sent when necessary.
|
626 |
|
|
3. If accept_ra is TRUE (default), accept Router
|
627 |
|
|
Advertisements (and do autoconfiguration).
|
628 |
|
|
4. If accept_redirects is TRUE (default), accept Redirects.
|
629 |
|
|
|
630 |
|
|
TRUE:
|
631 |
|
|
|
632 |
|
|
If local forwarding is enabled, Router behaviour is assumed.
|
633 |
|
|
This means exactly the reverse from the above:
|
634 |
|
|
|
635 |
|
|
1. IsRouter flag is set in Neighbour Advertisements.
|
636 |
|
|
2. Router Solicitations are not sent.
|
637 |
|
|
3. Router Advertisements are ignored.
|
638 |
|
|
4. Redirects are ignored.
|
639 |
|
|
|
640 |
|
|
Default: FALSE if global forwarding is disabled (default),
|
641 |
|
|
otherwise TRUE.
|
642 |
|
|
|
643 |
|
|
hop_limit - INTEGER
|
644 |
|
|
Default Hop Limit to set.
|
645 |
|
|
Default: 64
|
646 |
|
|
|
647 |
|
|
mtu - INTEGER
|
648 |
|
|
Default Maximum Transfer Unit
|
649 |
|
|
Default: 1280 (IPv6 required minimum)
|
650 |
|
|
|
651 |
|
|
router_solicitation_delay - INTEGER
|
652 |
|
|
Number of seconds to wait after interface is brought up
|
653 |
|
|
before sending Router Solicitations.
|
654 |
|
|
Default: 1
|
655 |
|
|
|
656 |
|
|
router_solicitation_interval - INTEGER
|
657 |
|
|
Number of seconds to wait between Router Solicitations.
|
658 |
|
|
Default: 4
|
659 |
|
|
|
660 |
|
|
router_solicitations - INTEGER
|
661 |
|
|
Number of Router Solicitations to send until assuming no
|
662 |
|
|
routers are present.
|
663 |
|
|
Default: 3
|
664 |
|
|
|
665 |
|
|
icmp/*:
|
666 |
|
|
ratelimit - INTEGER
|
667 |
|
|
Limit the maximal rates for sending ICMPv6 packets.
|
668 |
|
|
|
669 |
|
|
Default: 100
|
670 |
|
|
|
671 |
|
|
IPv6 Update by:
|
672 |
|
|
Pekka Savola
|
673 |
|
|
YOSHIFUJI Hideaki / USAGI Project
|
674 |
|
|
|
675 |
|
|
$Id: ip-sysctl.txt,v 1.1.1.1 2004-04-15 02:33:46 phoenix Exp $
|