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42 lines
1.7 KiB
42 lines
1.7 KiB
Allows you to restrict the number of parallel connections to a server per |
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client IP address (or client address block). |
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.TP |
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\fB\-\-connlimit\-upto\fP \fIn\fP |
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Match if the number of existing connections is below or equal \fIn\fP. |
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.TP |
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\fB\-\-connlimit\-above\fP \fIn\fP |
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Match if the number of existing connections is above \fIn\fP. |
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.TP |
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\fB\-\-connlimit\-mask\fP \fIprefix_length\fP |
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Group hosts using the prefix length. For IPv4, this must be a number between |
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(including) 0 and 32. For IPv6, between 0 and 128. If not specified, the |
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maximum prefix length for the applicable protocol is used. |
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.TP |
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\fB\-\-connlimit\-saddr\fP |
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Apply the limit onto the source group. This is the default if |
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\-\-connlimit\-daddr is not specified. |
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.TP |
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\fB\-\-connlimit\-daddr\fP |
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Apply the limit onto the destination group. |
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.PP |
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Examples: |
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.TP |
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# allow 2 telnet connections per client host |
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iptables \-A INPUT \-p tcp \-\-syn \-\-dport 23 \-m connlimit \-\-connlimit\-above 2 \-j REJECT |
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.TP |
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# you can also match the other way around: |
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iptables \-A INPUT \-p tcp \-\-syn \-\-dport 23 \-m connlimit \-\-connlimit\-upto 2 \-j ACCEPT |
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.TP |
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# limit the number of parallel HTTP requests to 16 per class C sized \ |
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source network (24 bit netmask) |
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iptables \-p tcp \-\-syn \-\-dport 80 \-m connlimit \-\-connlimit\-above 16 |
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\-\-connlimit\-mask 24 \-j REJECT |
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.TP |
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# limit the number of parallel HTTP requests to 16 for the link local network |
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(ipv6) |
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ip6tables \-p tcp \-\-syn \-\-dport 80 \-s fe80::/64 \-m connlimit \-\-connlimit\-above |
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16 \-\-connlimit\-mask 64 \-j REJECT |
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.TP |
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# Limit the number of connections to a particular host: |
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ip6tables \-p tcp \-\-syn \-\-dport 49152:65535 \-d 2001:db8::1 \-m connlimit |
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\-\-connlimit-above 100 \-j REJECT
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