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13df433f MCC |
1 | .. SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | =================================== | |
4 | Netfilter Conntrack Sysfs variables | |
5 | =================================== | |
6 | ||
c9f9e0e1 | 7 | /proc/sys/net/netfilter/nf_conntrack_* Variables: |
13df433f | 8 | ================================================= |
c9f9e0e1 JP |
9 | |
10 | nf_conntrack_acct - BOOLEAN | |
13df433f MCC |
11 | - 0 - disabled (default) |
12 | - not 0 - enabled | |
c9f9e0e1 JP |
13 | |
14 | Enable connection tracking flow accounting. 64-bit byte and packet | |
15 | counters per flow are added. | |
16 | ||
3183ab89 | 17 | nf_conntrack_buckets - INTEGER |
c9f9e0e1 JP |
18 | Size of hash table. If not specified as parameter during module |
19 | loading, the default size is calculated by dividing total memory | |
d532bcd0 FW |
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. | |
3183ab89 | 22 | This sysctl is only writeable in the initial net namespace. |
c9f9e0e1 JP |
23 | |
24 | nf_conntrack_checksum - BOOLEAN | |
13df433f MCC |
25 | - 0 - disabled |
26 | - not 0 - enabled (default) | |
c9f9e0e1 JP |
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 | ||
32 | nf_conntrack_count - INTEGER (read-only) | |
33 | Number of currently allocated flow entries. | |
34 | ||
35 | nf_conntrack_events - BOOLEAN | |
13df433f | 36 | - 0 - disabled |
90d1daa4 FW |
37 | - 1 - enabled |
38 | - 2 - auto (default) | |
c9f9e0e1 JP |
39 | |
40 | If this option is enabled, the connection tracking code will | |
41 | provide userspace with connection tracking events via ctnetlink. | |
90d1daa4 FW |
42 | The default allocates the extension if a userspace program is |
43 | listening to ctnetlink events. | |
c9f9e0e1 | 44 | |
c9f9e0e1 JP |
45 | nf_conntrack_expect_max - INTEGER |
46 | Maximum size of expectation table. Default value is | |
47 | nf_conntrack_buckets / 256. Minimum is 1. | |
48 | ||
49 | nf_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 | ||
57 | nf_conntrack_frag6_low_thresh - INTEGER | |
58 | default 196608 | |
59 | ||
60 | See nf_conntrack_frag6_low_thresh | |
61 | ||
62 | nf_conntrack_frag6_timeout - INTEGER (seconds) | |
63 | default 60 | |
64 | ||
65 | Time to keep an IPv6 fragment in memory. | |
66 | ||
67 | nf_conntrack_generic_timeout - INTEGER (seconds) | |
68 | default 600 | |
69 | ||
70 | Default for generic timeout. This refers to layer 4 unknown/unsupported | |
71 | protocols. | |
72 | ||
73 | nf_conntrack_helper - BOOLEAN | |
13df433f MCC |
74 | - 0 - disabled (default) |
75 | - not 0 - enabled | |
c9f9e0e1 JP |
76 | |
77 | Enable automatic conntrack helper assignment. | |
486dcf43 FW |
78 | If disabled it is required to set up iptables rules to assign |
79 | helpers to connections. See the CT target description in the | |
80 | iptables-extensions(8) man page for further information. | |
c9f9e0e1 JP |
81 | |
82 | nf_conntrack_icmp_timeout - INTEGER (seconds) | |
83 | default 30 | |
84 | ||
85 | Default for ICMP timeout. | |
86 | ||
87 | nf_conntrack_icmpv6_timeout - INTEGER (seconds) | |
88 | default 30 | |
89 | ||
90 | Default for ICMP6 timeout. | |
91 | ||
92 | nf_conntrack_log_invalid - INTEGER | |
13df433f MCC |
93 | - 0 - disable (default) |
94 | - 1 - log ICMP packets | |
95 | - 6 - log TCP packets | |
96 | - 17 - log UDP packets | |
97 | - 33 - log DCCP packets | |
98 | - 41 - log ICMPv6 packets | |
99 | - 136 - log UDPLITE packets | |
100 | - 255 - log packets of any protocol | |
c9f9e0e1 JP |
101 | |
102 | Log invalid packets of a type specified by value. | |
103 | ||
104 | nf_conntrack_max - INTEGER | |
d532bcd0 FW |
105 | Maximum number of allowed connection tracking entries. This value is set |
106 | to nf_conntrack_buckets by default. | |
107 | Note that connection tracking entries are added to the table twice -- once | |
108 | for the original direction and once for the reply direction (i.e., with | |
109 | the reversed address). This means that with default settings a maxed-out | |
110 | table will have a average hash chain length of 2, not 1. | |
c9f9e0e1 JP |
111 | |
112 | nf_conntrack_tcp_be_liberal - BOOLEAN | |
13df433f MCC |
113 | - 0 - disabled (default) |
114 | - not 0 - enabled | |
c9f9e0e1 JP |
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 | ||
1da4cd82 AA |
119 | nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN |
120 | - 0 - disabled (default) | |
121 | - 1 - enabled | |
122 | ||
123 | If it's 1, we don't mark out of window RST segments as INVALID. | |
124 | ||
c9f9e0e1 | 125 | nf_conntrack_tcp_loose - BOOLEAN |
13df433f MCC |
126 | - 0 - disabled |
127 | - not 0 - enabled (default) | |
c9f9e0e1 JP |
128 | |
129 | If it is set to zero, we disable picking up already established | |
130 | connections. | |
131 | ||
132 | nf_conntrack_tcp_max_retrans - INTEGER | |
133 | default 3 | |
134 | ||
135 | Maximum number of packets that can be retransmitted without | |
136 | received an (acceptable) ACK from the destination. If this number | |
137 | is reached, a shorter timer will be started. | |
138 | ||
139 | nf_conntrack_tcp_timeout_close - INTEGER (seconds) | |
140 | default 10 | |
141 | ||
142 | nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds) | |
143 | default 60 | |
144 | ||
145 | nf_conntrack_tcp_timeout_established - INTEGER (seconds) | |
146 | default 432000 (5 days) | |
147 | ||
148 | nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds) | |
149 | default 120 | |
150 | ||
151 | nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds) | |
152 | default 30 | |
153 | ||
154 | nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds) | |
155 | default 300 | |
156 | ||
157 | nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds) | |
158 | default 60 | |
159 | ||
160 | nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds) | |
161 | default 120 | |
162 | ||
163 | nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds) | |
164 | default 120 | |
165 | ||
166 | nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds) | |
167 | default 300 | |
168 | ||
169 | nf_conntrack_timestamp - BOOLEAN | |
13df433f MCC |
170 | - 0 - disabled (default) |
171 | - not 0 - enabled | |
c9f9e0e1 JP |
172 | |
173 | Enable connection tracking flow timestamping. | |
174 | ||
175 | nf_conntrack_udp_timeout - INTEGER (seconds) | |
176 | default 30 | |
177 | ||
bb38ccce | 178 | nf_conntrack_udp_timeout_stream - INTEGER (seconds) |
294304e4 | 179 | default 120 |
c9f9e0e1 JP |
180 | |
181 | This extended timeout will be used in case there is an UDP stream | |
182 | detected. | |
a0badcc6 YS |
183 | |
184 | nf_conntrack_gre_timeout - INTEGER (seconds) | |
185 | default 30 | |
186 | ||
187 | nf_conntrack_gre_timeout_stream - INTEGER (seconds) | |
188 | default 180 | |
189 | ||
190 | This extended timeout will be used in case there is an GRE stream | |
191 | detected. | |
3078d964 | 192 | |
7a3f5b0d RS |
193 | nf_hooks_lwtunnel - BOOLEAN |
194 | - 0 - disabled (default) | |
195 | - not 0 - enabled | |
196 | ||
197 | If this option is enabled, the lightweight tunnel netfilter hooks are | |
198 | enabled. This option cannot be disabled once it is enabled. | |
199 | ||
3078d964 OS |
200 | nf_flowtable_tcp_timeout - INTEGER (seconds) |
201 | default 30 | |
202 | ||
203 | Control offload timeout for tcp connections. | |
204 | TCP connections may be offloaded from nf conntrack to nf flow table. | |
205 | Once aged, the connection is returned to nf conntrack with tcp pickup timeout. | |
206 | ||
3078d964 OS |
207 | nf_flowtable_udp_timeout - INTEGER (seconds) |
208 | default 30 | |
209 | ||
210 | Control offload timeout for udp connections. | |
211 | UDP connections may be offloaded from nf conntrack to nf flow table. | |
212 | Once aged, the connection is returned to nf conntrack with udp pickup timeout. |