iproute2 rules and iptables NAT... what is the difference?

Posted by Jakobud on Server Fault See other posts from Server Fault or by Jakobud
Published on 2010-04-22T22:01:13Z Indexed on 2010/04/22 22:03 UTC
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iproute2

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iptables

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firewall

We have 2 different ISP connections. Our previous "IT guy" setup our firewall like so:

When /etc/rc.local was executed on startup, it did a bunch of ip rule add and ip route add commands in order to route certain internal hosts to use certain ISP connections.

Then at the end of /etc/rc.local, he executed our iptables firewall rules that were generated by Firewall Builder. These iptables rules have both Policy and NAT rules setup in them.

What I don't understand, is why did he use iproute2 to specify rules and routes but also specify NAT rules for iptables? Why didn't he just do it all in one or the other instead of using them both? Could he have got rid of the iproute2 rules and routes and just put all those same rules into the iptables NAT settings?

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