Parallel connections are patched with
Patchomatic
specifically the
connlimit patch
Instructions are inside the patchomatic directory after extracting the download.
The base/connlimit patch:
Author: Gerd Knorr <kraxel@bytesex.org>
Status: ItWorksForMe[tm]
This adds CONFIG_IP_NF_MATCH_CONNLIMIT match allows you to restrict the
number of parallel TCP connections to a server per client IP address
(or address block).
Examples:
# allow 2 telnet connections per client host
iptables -p tcp --syn --dport 23 -m connlimit --connlimit-above 2 -j REJECT
# you can also match the other way around:
iptables -p tcp --syn --dport 23 -m connlimit ! --connlimit-above 2 -j ACCEPT
# limit the nr of parallel http requests to 16 per class C sized
# network (24 bit netmask)
iptables -p tcp --syn --dport 80 -m connlimit --connlimit-above 16 --connlimit-mask 24 -j REJECT
