Documentation/networking/nf_conntrack-sysctl.txt

   1 /proc/sys/net/netfilter/nf_conntrack_* Variables:
   2
   3 nf_conntrack_acct - BOOLEAN
   4         0 - disabled (default)
   5         not 0 - enabled
   6
   7         Enable connection tracking flow accounting. 64-bit byte and packet
   8         counters per flow are added.
   9
  10 nf_conntrack_buckets - INTEGER
  11         Size of hash table. If not specified as parameter during module
  12         loading, the default size is calculated by dividing total memory
  13         by 16384 to determine the number of buckets but the hash table will
  14         never have fewer than 32 and limited to 16384 buckets. For systems
  15         with more than 4GB of memory it will be 65536 buckets.
  16         This sysctl is only writeable in the initial net namespace.
  17
  18 nf_conntrack_checksum - BOOLEAN
  19         0 - disabled
  20         not 0 - enabled (default)
  21
  22         Verify checksum of incoming packets. Packets with bad checksums are
  23         in INVALID state. If this is enabled, such packets will not be
  24         considered for connection tracking.
  25
  26 nf_conntrack_count - INTEGER (read-only)
  27         Number of currently allocated flow entries.
  28
  29 nf_conntrack_events - BOOLEAN
  30         0 - disabled
  31         not 0 - enabled (default)
  32
  33         If this option is enabled, the connection tracking code will
  34         provide userspace with connection tracking events via ctnetlink.
  35
  36 nf_conntrack_expect_max - INTEGER
  37         Maximum size of expectation table.  Default value is
  38         nf_conntrack_buckets / 256. Minimum is 1.
  39
  40 nf_conntrack_frag6_high_thresh - INTEGER
  41         default 262144
  42
  43         Maximum memory used to reassemble IPv6 fragments.  When
  44         nf_conntrack_frag6_high_thresh bytes of memory is allocated for this
  45         purpose, the fragment handler will toss packets until
  46         nf_conntrack_frag6_low_thresh is reached.
  47
  48 nf_conntrack_frag6_low_thresh - INTEGER
  49         default 196608
  50
  51         See nf_conntrack_frag6_low_thresh
  52
  53 nf_conntrack_frag6_timeout - INTEGER (seconds)
  54         default 60
  55
  56         Time to keep an IPv6 fragment in memory.
  57
  58 nf_conntrack_generic_timeout - INTEGER (seconds)
  59         default 600
  60
  61         Default for generic timeout.  This refers to layer 4 unknown/unsupported
  62         protocols.
  63
  64 nf_conntrack_helper - BOOLEAN
  65         0 - disabled (default)
  66         not 0 - enabled
  67
  68         Enable automatic conntrack helper assignment.
  69         If disabled it is required to set up iptables rules to assign
  70         helpers to connections.  See the CT target description in the
  71         iptables-extensions(8) man page for further information.
  72
  73 nf_conntrack_icmp_timeout - INTEGER (seconds)
  74         default 30
  75
  76         Default for ICMP timeout.
  77
  78 nf_conntrack_icmpv6_timeout - INTEGER (seconds)
  79         default 30
  80
  81         Default for ICMP6 timeout.
  82
  83 nf_conntrack_log_invalid - INTEGER
  84         0   - disable (default)
  85         1   - log ICMP packets
  86         6   - log TCP packets
  87         17  - log UDP packets
  88         33  - log DCCP packets
  89         41  - log ICMPv6 packets
  90         136 - log UDPLITE packets
  91         255 - log packets of any protocol
  92
  93         Log invalid packets of a type specified by value.
  94
  95 nf_conntrack_max - INTEGER
  96         Size of connection tracking table.  Default value is
  97         nf_conntrack_buckets value * 4.
  98
  99 nf_conntrack_tcp_be_liberal - BOOLEAN
 100         0 - disabled (default)
 101         not 0 - enabled
 102
 103         Be conservative in what you do, be liberal in what you accept from others.
 104         If it's non-zero, we mark only out of window RST segments as INVALID.
 105
 106 nf_conntrack_tcp_loose - BOOLEAN
 107         0 - disabled
 108         not 0 - enabled (default)
 109
 110         If it is set to zero, we disable picking up already established
 111         connections.
 112
 113 nf_conntrack_tcp_max_retrans - INTEGER
 114         default 3
 115
 116         Maximum number of packets that can be retransmitted without
 117         received an (acceptable) ACK from the destination. If this number
 118         is reached, a shorter timer will be started.
 119
 120 nf_conntrack_tcp_timeout_close - INTEGER (seconds)
 121         default 10
 122
 123 nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds)
 124         default 60
 125
 126 nf_conntrack_tcp_timeout_established - INTEGER (seconds)
 127         default 432000 (5 days)
 128
 129 nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds)
 130         default 120
 131
 132 nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds)
 133         default 30
 134
 135 nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds)
 136         default 300
 137
 138 nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds)
 139         default 60
 140
 141 nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds)
 142         default 120
 143
 144 nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds)
 145         default 120
 146
 147 nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds)
 148         default 300
 149
 150 nf_conntrack_timestamp - BOOLEAN
 151         0 - disabled (default)
 152         not 0 - enabled
 153
 154         Enable connection tracking flow timestamping.
 155
 156 nf_conntrack_udp_timeout - INTEGER (seconds)
 157         default 30
 158
 159 nf_conntrack_udp_timeout_stream2 - INTEGER (seconds)
 160         default 180
 161
 162         This extended timeout will be used in case there is an UDP stream
 163         detected.