MASQUERADING

Jan Engelhardt jengelh at linux01.gwdg.de
Thu Jul 21 13:54:03 CEST 2005


>> Suppose I masquerade ppp0 using
>> iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
>> 
>> And now all packets will have a src ip addr as 192.168.0.2 will be
>> changed to that of ppp0 , for example say 10.10.10.1

No, it does not say "changed to that of ppp0" but:
_change_all_packets_that_go_out_of_ppp0_ (...to the address belonging to ppp0)

>> Now my question is, when the reply comes, their destination addr will be
>> that of ppp0 i.e 10.10.10.1
>> Who will reverse translate this 10.10.10.1 destination addr to actual
>> 192.168.0.2 ?

>This is the job of connection tracking, basically ipt_conntrack.

Nitpick: ip_conntrack.
ipt_conntrack is the module for the -m conntrack match used by iptables.


Jan Engelhardt
-- 



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