[Firehol-support] Adding custom iptables rules to firehol config

Daniel L. Miller dmiller at amfes.com
Tue Jun 21 19:57:11 BST 2011

I wanted to try some "simple" iptables rules to see if they have an 
effect on my traffic.  I found these on some of the traffic shaping 
sites.  Do I simply add these at the top of my script before any other 
firehol commands - or is there a better way?

version 5
source /etc/firehol/shaper.conf

# Adjust TOS flags to ensure speedy ssh
iptables -t mangle -N tosfix
iptables -t mangle -A tosfix -p tcp -m length --length 0:512 -j RETURN
iptables -t mangle -A tosfix -m limit --limit 2/s --limit-burst 10 -j RETURN
iptables -t mangle -A tosfix -j TOS --set-tos Maximize-Throughput
iptables -t mangle -A tosfix -j RETURN
iptables -t mangle -A POSTROUTING -p tcp -m tos --tos Minimize-Delay -j 

# Tune ack packets
iptables -t mangle -N ack
iptables -t mangle -A ack -m tos ! --tos Normal-Service -j RETURN
iptables -t mangle -A ack -p tcp -m length --length 0:128 \
   -j TOS --set-tos Minimize-Delay
iptables -t mangle -A ack -p tcp -m length --length 128: \
   -j TOS --set-tos Maximize-Throughput
iptables -t mangle -A ack -j RETURN
iptables -t mangle -A POSTROUTING -p tcp -m tcp --tcp-flags SYN,RST,ACK 
ACK -j ack



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