210 lines
6.0 KiB
ReStructuredText
210 lines
6.0 KiB
ReStructuredText
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.. SPDX-License-Identifier: GPL-2.0
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===================================
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Netfilter Conntrack Sysfs variables
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===================================
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/proc/sys/net/netfilter/nf_conntrack_* Variables:
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=================================================
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nf_conntrack_acct - BOOLEAN
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- 0 - disabled (default)
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- not 0 - enabled
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Enable connection tracking flow accounting. 64-bit byte and packet
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counters per flow are added.
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nf_conntrack_buckets - INTEGER
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Size of hash table. If not specified as parameter during module
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loading, the default size is calculated by dividing total memory
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by 16384 to determine the number of buckets. The hash table will
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never have fewer than 1024 and never more than 262144 buckets.
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This sysctl is only writeable in the initial net namespace.
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nf_conntrack_checksum - BOOLEAN
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- 0 - disabled
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- not 0 - enabled (default)
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Verify checksum of incoming packets. Packets with bad checksums are
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in INVALID state. If this is enabled, such packets will not be
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considered for connection tracking.
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nf_conntrack_count - INTEGER (read-only)
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Number of currently allocated flow entries.
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nf_conntrack_events - BOOLEAN
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- 0 - disabled
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- not 0 - enabled (default)
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If this option is enabled, the connection tracking code will
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provide userspace with connection tracking events via ctnetlink.
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nf_conntrack_expect_max - INTEGER
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Maximum size of expectation table. Default value is
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nf_conntrack_buckets / 256. Minimum is 1.
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nf_conntrack_frag6_high_thresh - INTEGER
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default 262144
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Maximum memory used to reassemble IPv6 fragments. When
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nf_conntrack_frag6_high_thresh bytes of memory is allocated for this
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purpose, the fragment handler will toss packets until
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nf_conntrack_frag6_low_thresh is reached.
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nf_conntrack_frag6_low_thresh - INTEGER
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default 196608
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See nf_conntrack_frag6_low_thresh
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nf_conntrack_frag6_timeout - INTEGER (seconds)
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default 60
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Time to keep an IPv6 fragment in memory.
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nf_conntrack_generic_timeout - INTEGER (seconds)
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default 600
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Default for generic timeout. This refers to layer 4 unknown/unsupported
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protocols.
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nf_conntrack_helper - BOOLEAN
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- 0 - disabled (default)
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- not 0 - enabled
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Enable automatic conntrack helper assignment.
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If disabled it is required to set up iptables rules to assign
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helpers to connections. See the CT target description in the
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iptables-extensions(8) man page for further information.
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nf_conntrack_icmp_timeout - INTEGER (seconds)
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default 30
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Default for ICMP timeout.
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nf_conntrack_icmpv6_timeout - INTEGER (seconds)
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default 30
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Default for ICMP6 timeout.
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nf_conntrack_log_invalid - INTEGER
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- 0 - disable (default)
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- 1 - log ICMP packets
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- 6 - log TCP packets
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- 17 - log UDP packets
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- 33 - log DCCP packets
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- 41 - log ICMPv6 packets
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- 136 - log UDPLITE packets
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- 255 - log packets of any protocol
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Log invalid packets of a type specified by value.
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nf_conntrack_max - INTEGER
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Maximum number of allowed connection tracking entries. This value is set
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to nf_conntrack_buckets by default.
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Note that connection tracking entries are added to the table twice -- once
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for the original direction and once for the reply direction (i.e., with
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the reversed address). This means that with default settings a maxed-out
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table will have a average hash chain length of 2, not 1.
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nf_conntrack_tcp_be_liberal - BOOLEAN
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- 0 - disabled (default)
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- not 0 - enabled
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Be conservative in what you do, be liberal in what you accept from others.
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If it's non-zero, we mark only out of window RST segments as INVALID.
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nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN
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- 0 - disabled (default)
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- 1 - enabled
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If it's 1, we don't mark out of window RST segments as INVALID.
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nf_conntrack_tcp_loose - BOOLEAN
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- 0 - disabled
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- not 0 - enabled (default)
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If it is set to zero, we disable picking up already established
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connections.
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nf_conntrack_tcp_max_retrans - INTEGER
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default 3
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Maximum number of packets that can be retransmitted without
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received an (acceptable) ACK from the destination. If this number
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is reached, a shorter timer will be started.
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nf_conntrack_tcp_timeout_close - INTEGER (seconds)
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default 10
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nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds)
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default 60
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nf_conntrack_tcp_timeout_established - INTEGER (seconds)
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default 432000 (5 days)
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nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds)
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default 120
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nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds)
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default 30
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nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds)
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default 300
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nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds)
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default 60
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nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds)
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default 120
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nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds)
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default 120
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nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds)
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default 300
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nf_conntrack_timestamp - BOOLEAN
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- 0 - disabled (default)
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- not 0 - enabled
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Enable connection tracking flow timestamping.
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nf_conntrack_udp_timeout - INTEGER (seconds)
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default 30
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nf_conntrack_udp_timeout_stream - INTEGER (seconds)
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default 120
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This extended timeout will be used in case there is an UDP stream
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detected.
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nf_conntrack_gre_timeout - INTEGER (seconds)
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default 30
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nf_conntrack_gre_timeout_stream - INTEGER (seconds)
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default 180
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This extended timeout will be used in case there is an GRE stream
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detected.
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nf_hooks_lwtunnel - BOOLEAN
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- 0 - disabled (default)
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- not 0 - enabled
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If this option is enabled, the lightweight tunnel netfilter hooks are
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enabled. This option cannot be disabled once it is enabled.
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nf_flowtable_tcp_timeout - INTEGER (seconds)
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default 30
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Control offload timeout for tcp connections.
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TCP connections may be offloaded from nf conntrack to nf flow table.
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Once aged, the connection is returned to nf conntrack with tcp pickup timeout.
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nf_flowtable_udp_timeout - INTEGER (seconds)
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default 30
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Control offload timeout for udp connections.
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UDP connections may be offloaded from nf conntrack to nf flow table.
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Once aged, the connection is returned to nf conntrack with udp pickup timeout.
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