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Quick question but Gooling has not revealed an answer. When I do iptables -L, it seems to lag on displaying items in where I have limited the source to internal ips 192.168.0.0/24

The whole listing takes about 30 seconds to display.

I just want to know: Does this affect the speed of my incoming connections or is this simply a side effect of having all these ranges within my iptables rules?

Thanks!

62

Include the -n option so it doesn't try to use DNS to resolve names for every ip address, network and port. Then it will be fast.

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    I generally like iptables -vnL --line-numbers for my listing command. Keep in mind by default you don't see all the tables, for instance, the nat table. To see that nat table: -t nat – Kyle Brandt Nov 17 '09 at 17:50
  • -t mangle & -t raw also are not displayed by default – Stuart Cardall Apr 6 '18 at 18:28
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I've personally seen this happen on a server that was configured for LDAP authentication, but could not reach the LDAP server (this was SLED 10). In my case, "netstat -a" and "iptables -L" were both exhibiting the same behavior you describe. An "strace" of the netstat showed it hanging on a connection to port 636 (LDAP-Secure). Turning off the LDAP (which, for me, was not needed on this platform) fixed the problem.

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