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I am trying to configure iptables for ubuntu 10.04 and I have a problem with iptables -L lagging on rows where the destination or source address is not localhost or anywhere. The following entries will cause lag on their row:

iptables -A INPUT -p tcp --dport 111-s -j ACCEPT
iptables -A INPUT -p tcp --dport 90 -d -j ACCEPT

while this does not:

iptables -A INPUT -p tcp --dport 111 -j ACCEPT
iptables -A INPUT -p tcp --dport 90 -j ACCEPT

I feel like this might be due to iptables checking to see if the ip is reachable. If not, what is the cause, if it is how can I disable it?

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up vote 2 down vote accepted

It's trying to resolve addresses to hostnames. Adding -n will prevent this.

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