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Diffstat (limited to 'Documentation/networking/nf_conntrack-sysctl.rst')
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diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst new file mode 100644 index 000000000000..11a9b76786cb --- /dev/null +++ b/Documentation/networking/nf_conntrack-sysctl.rst @@ -0,0 +1,179 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Netfilter Conntrack Sysfs variables +=================================== + +/proc/sys/net/netfilter/nf_conntrack_* Variables: +================================================= + +nf_conntrack_acct - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Enable connection tracking flow accounting. 64-bit byte and packet + counters per flow are added. + +nf_conntrack_buckets - INTEGER + Size of hash table. If not specified as parameter during module + loading, the default size is calculated by dividing total memory + by 16384 to determine the number of buckets but the hash table will + never have fewer than 32 and limited to 16384 buckets. For systems + with more than 4GB of memory it will be 65536 buckets. + This sysctl is only writeable in the initial net namespace. + +nf_conntrack_checksum - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + Verify checksum of incoming packets. Packets with bad checksums are + in INVALID state. If this is enabled, such packets will not be + considered for connection tracking. + +nf_conntrack_count - INTEGER (read-only) + Number of currently allocated flow entries. + +nf_conntrack_events - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + If this option is enabled, the connection tracking code will + provide userspace with connection tracking events via ctnetlink. + +nf_conntrack_expect_max - INTEGER + Maximum size of expectation table. Default value is + nf_conntrack_buckets / 256. Minimum is 1. + +nf_conntrack_frag6_high_thresh - INTEGER + default 262144 + + Maximum memory used to reassemble IPv6 fragments. When + nf_conntrack_frag6_high_thresh bytes of memory is allocated for this + purpose, the fragment handler will toss packets until + nf_conntrack_frag6_low_thresh is reached. + +nf_conntrack_frag6_low_thresh - INTEGER + default 196608 + + See nf_conntrack_frag6_low_thresh + +nf_conntrack_frag6_timeout - INTEGER (seconds) + default 60 + + Time to keep an IPv6 fragment in memory. + +nf_conntrack_generic_timeout - INTEGER (seconds) + default 600 + + Default for generic timeout. This refers to layer 4 unknown/unsupported + protocols. + +nf_conntrack_helper - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Enable automatic conntrack helper assignment. + If disabled it is required to set up iptables rules to assign + helpers to connections. See the CT target description in the + iptables-extensions(8) man page for further information. + +nf_conntrack_icmp_timeout - INTEGER (seconds) + default 30 + + Default for ICMP timeout. + +nf_conntrack_icmpv6_timeout - INTEGER (seconds) + default 30 + + Default for ICMP6 timeout. + +nf_conntrack_log_invalid - INTEGER + - 0 - disable (default) + - 1 - log ICMP packets + - 6 - log TCP packets + - 17 - log UDP packets + - 33 - log DCCP packets + - 41 - log ICMPv6 packets + - 136 - log UDPLITE packets + - 255 - log packets of any protocol + + Log invalid packets of a type specified by value. + +nf_conntrack_max - INTEGER + Size of connection tracking table. Default value is + nf_conntrack_buckets value * 4. + +nf_conntrack_tcp_be_liberal - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Be conservative in what you do, be liberal in what you accept from others. + If it's non-zero, we mark only out of window RST segments as INVALID. + +nf_conntrack_tcp_loose - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + If it is set to zero, we disable picking up already established + connections. + +nf_conntrack_tcp_max_retrans - INTEGER + default 3 + + Maximum number of packets that can be retransmitted without + received an (acceptable) ACK from the destination. If this number + is reached, a shorter timer will be started. + +nf_conntrack_tcp_timeout_close - INTEGER (seconds) + default 10 + +nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds) + default 60 + +nf_conntrack_tcp_timeout_established - INTEGER (seconds) + default 432000 (5 days) + +nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds) + default 30 + +nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds) + default 300 + +nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds) + default 60 + +nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds) + default 300 + +nf_conntrack_timestamp - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Enable connection tracking flow timestamping. + +nf_conntrack_udp_timeout - INTEGER (seconds) + default 30 + +nf_conntrack_udp_timeout_stream - INTEGER (seconds) + default 120 + + This extended timeout will be used in case there is an UDP stream + detected. + +nf_conntrack_gre_timeout - INTEGER (seconds) + default 30 + +nf_conntrack_gre_timeout_stream - INTEGER (seconds) + default 180 + + This extended timeout will be used in case there is an GRE stream + detected. |