Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1.. SPDX-License-Identifier: GPL-2.0
2
3===================================
4Netfilter Conntrack Sysfs variables
5===================================
6
7/proc/sys/net/netfilter/nf_conntrack_* Variables:
8=================================================
9
10nf_conntrack_acct - BOOLEAN
11 - 0 - disabled (default)
12 - not 0 - enabled
13
14 Enable connection tracking flow accounting. 64-bit byte and packet
15 counters per flow are added.
16
17nf_conntrack_buckets - INTEGER
18 Size of hash table. If not specified as parameter during module
19 loading, the default size is calculated by dividing total memory
20 by 16384 to determine the number of buckets. The hash table will
21 never have fewer than 1024 and never more than 262144 buckets.
22 This sysctl is only writeable in the initial net namespace.
23
24nf_conntrack_checksum - BOOLEAN
25 - 0 - disabled
26 - not 0 - enabled (default)
27
28 Verify checksum of incoming packets. Packets with bad checksums are
29 in INVALID state. If this is enabled, such packets will not be
30 considered for connection tracking.
31
32nf_conntrack_count - INTEGER (read-only)
33 Number of currently allocated flow entries.
34
35nf_conntrack_events - BOOLEAN
36 - 0 - disabled
37 - 1 - enabled
38 - 2 - auto (default)
39
40 If this option is enabled, the connection tracking code will
41 provide userspace with connection tracking events via ctnetlink.
42 The default allocates the extension if a userspace program is
43 listening to ctnetlink events.
44
45nf_conntrack_expect_max - INTEGER
46 Maximum size of expectation table. Default value is
47 nf_conntrack_buckets / 256. Minimum is 1.
48
49nf_conntrack_frag6_high_thresh - INTEGER
50 default 262144
51
52 Maximum memory used to reassemble IPv6 fragments. When
53 nf_conntrack_frag6_high_thresh bytes of memory is allocated for this
54 purpose, the fragment handler will toss packets until
55 nf_conntrack_frag6_low_thresh is reached.
56
57nf_conntrack_frag6_low_thresh - INTEGER
58 default 196608
59
60 See nf_conntrack_frag6_low_thresh
61
62nf_conntrack_frag6_timeout - INTEGER (seconds)
63 default 60
64
65 Time to keep an IPv6 fragment in memory.
66
67nf_conntrack_generic_timeout - INTEGER (seconds)
68 default 600
69
70 Default for generic timeout. This refers to layer 4 unknown/unsupported
71 protocols.
72
73nf_conntrack_icmp_timeout - INTEGER (seconds)
74 default 30
75
76 Default for ICMP timeout.
77
78nf_conntrack_icmpv6_timeout - INTEGER (seconds)
79 default 30
80
81 Default for ICMP6 timeout.
82
83nf_conntrack_log_invalid - INTEGER
84 - 0 - disable (default)
85 - 1 - log ICMP packets
86 - 6 - log TCP packets
87 - 17 - log UDP packets
88 - 41 - log ICMPv6 packets
89 - 136 - log UDPLITE packets
90 - 255 - log packets of any protocol
91
92 Log invalid packets of a type specified by value.
93
94nf_conntrack_max - INTEGER
95 Maximum number of allowed connection tracking entries. This value is set
96 to nf_conntrack_buckets by default.
97 Note that connection tracking entries are added to the table twice -- once
98 for the original direction and once for the reply direction (i.e., with
99 the reversed address). This means that with default settings a maxed-out
100 table will have a average hash chain length of 2, not 1.
101
102nf_conntrack_tcp_be_liberal - BOOLEAN
103 - 0 - disabled (default)
104 - not 0 - enabled
105
106 Be conservative in what you do, be liberal in what you accept from others.
107 If it's non-zero, we mark only out of window RST segments as INVALID.
108
109nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN
110 - 0 - disabled (default)
111 - 1 - enabled
112
113 If it's 1, we don't mark out of window RST segments as INVALID.
114
115nf_conntrack_tcp_loose - BOOLEAN
116 - 0 - disabled
117 - not 0 - enabled (default)
118
119 If it is set to zero, we disable picking up already established
120 connections.
121
122nf_conntrack_tcp_max_retrans - INTEGER
123 default 3
124
125 Maximum number of packets that can be retransmitted without
126 received an (acceptable) ACK from the destination. If this number
127 is reached, a shorter timer will be started.
128
129nf_conntrack_tcp_timeout_close - INTEGER (seconds)
130 default 10
131
132nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds)
133 default 60
134
135nf_conntrack_tcp_timeout_established - INTEGER (seconds)
136 default 432000 (5 days)
137
138nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds)
139 default 120
140
141nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds)
142 default 30
143
144nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds)
145 default 300
146
147nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds)
148 default 60
149
150nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds)
151 default 120
152
153nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds)
154 default 120
155
156nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds)
157 default 300
158
159nf_conntrack_timestamp - BOOLEAN
160 - 0 - disabled (default)
161 - not 0 - enabled
162
163 Enable connection tracking flow timestamping.
164
165nf_conntrack_sctp_timeout_closed - INTEGER (seconds)
166 default 10
167
168nf_conntrack_sctp_timeout_cookie_wait - INTEGER (seconds)
169 default 3
170
171nf_conntrack_sctp_timeout_cookie_echoed - INTEGER (seconds)
172 default 3
173
174nf_conntrack_sctp_timeout_established - INTEGER (seconds)
175 default 210
176
177 Default is set to (hb_interval * path_max_retrans + rto_max)
178
179nf_conntrack_sctp_timeout_shutdown_sent - INTEGER (seconds)
180 default 3
181
182nf_conntrack_sctp_timeout_shutdown_recd - INTEGER (seconds)
183 default 3
184
185nf_conntrack_sctp_timeout_shutdown_ack_sent - INTEGER (seconds)
186 default 3
187
188nf_conntrack_sctp_timeout_heartbeat_sent - INTEGER (seconds)
189 default 30
190
191 This timeout is used to setup conntrack entry on secondary paths.
192 Default is set to hb_interval.
193
194nf_conntrack_udp_timeout - INTEGER (seconds)
195 default 30
196
197nf_conntrack_udp_timeout_stream - INTEGER (seconds)
198 default 120
199
200 This extended timeout will be used in case there is an UDP stream
201 detected.
202
203nf_conntrack_gre_timeout - INTEGER (seconds)
204 default 30
205
206nf_conntrack_gre_timeout_stream - INTEGER (seconds)
207 default 180
208
209 This extended timeout will be used in case there is an GRE stream
210 detected.
211
212nf_hooks_lwtunnel - BOOLEAN
213 - 0 - disabled (default)
214 - not 0 - enabled
215
216 If this option is enabled, the lightweight tunnel netfilter hooks are
217 enabled. This option cannot be disabled once it is enabled.
218
219nf_flowtable_tcp_timeout - INTEGER (seconds)
220 default 30
221
222 Control offload timeout for tcp connections.
223 TCP connections may be offloaded from nf conntrack to nf flow table.
224 Once aged, the connection is returned to nf conntrack.
225
226nf_flowtable_udp_timeout - INTEGER (seconds)
227 default 30
228
229 Control offload timeout for udp connections.
230 UDP connections may be offloaded from nf conntrack to nf flow table.
231 Once aged, the connection is returned to nf conntrack.