libxt_connlimit.man revision 2cae5334de3a817947742e0b466355e5f5566474
1Allows you to restrict the number of parallel connections to a server per 2client IP address (or client address block). 3.TP 4\fB\-\-connlimit\-upto\fP \fIn\fP 5Match if the number of existing connections is below or equal \fIn\fP. 6.TP 7\fB\-\-connlimit\-above\fP \fIn\fP 8Match if the number of existing connections is above \fIn\fP. 9.TP 10\fB\-\-connlimit\-mask\fP \fIprefix_length\fP 11Group hosts using the prefix length. For IPv4, this must be a number between 12(including) 0 and 32. For IPv6, between 0 and 128. If not specified, the 13maximum prefix length for the applicable protocol is used. 14.P 15Examples: 16.TP 17# allow 2 telnet connections per client host 18iptables \-A INPUT \-p tcp \-\-syn \-\-dport 23 \-m connlimit \-\-connlimit\-above 2 \-j REJECT 19.TP 20# you can also match the other way around: 21iptables \-A INPUT \-p tcp \-\-syn \-\-dport 23 \-m connlimit \-\-connlimit\-upto 2 \-j ACCEPT 22.TP 23# limit the number of parallel HTTP requests to 16 per class C sized \ 24network (24 bit netmask) 25iptables \-p tcp \-\-syn \-\-dport 80 \-m connlimit \-\-connlimit\-above 16 26\-\-connlimit\-mask 24 \-j REJECT 27.TP 28# limit the number of parallel HTTP requests to 16 for the link local network 29(ipv6) 30ip6tables \-p tcp \-\-syn \-\-dport 80 \-s fe80::/64 \-m connlimit \-\-connlimit\-above 3116 \-\-connlimit\-mask 64 \-j REJECT 32