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 (read-only)
  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 or more than 16384 buckets.
  15
  16 nf_conntrack_checksum - BOOLEAN
  17         0 - disabled
  18         not 0 - enabled (default)
  19
  20         Verify checksum of incoming packets. Packets with bad checksums are
  21         in INVALID state. If this is enabled, such packets will not be
  22         considered for connection tracking.
  23
  24 nf_conntrack_count - INTEGER (read-only)
  25         Number of currently allocated flow entries.
  26
  27 nf_conntrack_events - BOOLEAN
  28         0 - disabled
  29         not 0 - enabled (default)
  30
  31         If this option is enabled, the connection tracking code will
  32         provide userspace with connection tracking events via ctnetlink.
  33
  34 nf_conntrack_events_retry_timeout - INTEGER (seconds)
  35         default 15
  36
  37         This option is only relevant when "reliable connection tracking
  38         events" are used.  Normally, ctnetlink is "lossy", that is,
  39         events are normally dropped when userspace listeners can't keep up.
  40
  41         Userspace can request "reliable event mode".  When this mode is
  42         active, the conntrack will only be destroyed after the event was
  43         delivered.  If event delivery fails, the kernel periodically
  44         re-tries to send the event to userspace.
  45
  46         This is the maximum interval the kernel should use when re-trying
  47         to deliver the destroy event.
  48
  49         A higher number means there will be fewer delivery retries and it
  50         will take longer for a backlog to be processed.
  51
  52 nf_conntrack_expect_max - INTEGER
  53         Maximum size of expectation table.  Default value is
  54         nf_conntrack_buckets / 256. Minimum is 1.
  55
  56 nf_conntrack_frag6_high_thresh - INTEGER
  57         default 262144
  58
  59         Maximum memory used to reassemble IPv6 fragments.  When
  60         nf_conntrack_frag6_high_thresh bytes of memory is allocated for this
  61         purpose, the fragment handler will toss packets until
  62         nf_conntrack_frag6_low_thresh is reached.
  63
  64 nf_conntrack_frag6_low_thresh - INTEGER
  65         default 196608
  66
  67         See nf_conntrack_frag6_low_thresh
  68
  69 nf_conntrack_frag6_timeout - INTEGER (seconds)
  70         default 60
  71
  72         Time to keep an IPv6 fragment in memory.
  73
  74 nf_conntrack_generic_timeout - INTEGER (seconds)
  75         default 600
  76
  77         Default for generic timeout.  This refers to layer 4 unknown/unsupported
  78         protocols.
  79
  80 nf_conntrack_helper - BOOLEAN
  81         0 - disabled
  82         not 0 - enabled (default)
  83
  84         Enable automatic conntrack helper assignment.
  85
  86 nf_conntrack_icmp_timeout - INTEGER (seconds)
  87         default 30
  88
  89         Default for ICMP timeout.
  90
  91 nf_conntrack_icmpv6_timeout - INTEGER (seconds)
  92         default 30
  93
  94         Default for ICMP6 timeout.
  95
  96 nf_conntrack_log_invalid - INTEGER
  97         0   - disable (default)
  98         1   - log ICMP packets
  99         6   - log TCP packets
 100         17  - log UDP packets
 101         33  - log DCCP packets
 102         41  - log ICMPv6 packets
 103         136 - log UDPLITE packets
 104         255 - log packets of any protocol
 105
 106         Log invalid packets of a type specified by value.
 107
 108 nf_conntrack_max - INTEGER
 109         Size of connection tracking table.  Default value is
 110         nf_conntrack_buckets value * 4.
 111
 112 nf_conntrack_tcp_be_liberal - BOOLEAN
 113         0 - disabled (default)
 114         not 0 - enabled
 115
 116         Be conservative in what you do, be liberal in what you accept from others.
 117         If it's non-zero, we mark only out of window RST segments as INVALID.
 118
 119 nf_conntrack_tcp_loose - BOOLEAN
 120         0 - disabled
 121         not 0 - enabled (default)
 122
 123         If it is set to zero, we disable picking up already established
 124         connections.
 125
 126 nf_conntrack_tcp_max_retrans - INTEGER
 127         default 3
 128
 129         Maximum number of packets that can be retransmitted without
 130         received an (acceptable) ACK from the destination. If this number
 131         is reached, a shorter timer will be started.
 132
 133 nf_conntrack_tcp_timeout_close - INTEGER (seconds)
 134         default 10
 135
 136 nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds)
 137         default 60
 138
 139 nf_conntrack_tcp_timeout_established - INTEGER (seconds)
 140         default 432000 (5 days)
 141
 142 nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds)
 143         default 120
 144
 145 nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds)
 146         default 30
 147
 148 nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds)
 149         default 300
 150
 151 nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds)
 152         default 60
 153
 154 nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds)
 155         default 120
 156
 157 nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds)
 158         default 120
 159
 160 nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds)
 161         default 300
 162
 163 nf_conntrack_timestamp - BOOLEAN
 164         0 - disabled (default)
 165         not 0 - enabled
 166
 167         Enable connection tracking flow timestamping.
 168
 169 nf_conntrack_udp_timeout - INTEGER (seconds)
 170         default 30
 171
 172 nf_conntrack_udp_timeout_stream2 - INTEGER (seconds)
 173         default 180
 174
 175         This extended timeout will be used in case there is an UDP stream
 176         detected.