> Now what i would like to know is there a way I could route > all out going mail from 172.20.128.56 to 192.168.16.56 using > iptables DNAT. > > First of all, is it possible to do what I want to do? and The networks seem to be connected, so can't you just configure a smtp-forwarder in your MTA configuration ? That would be easier I think. > would I use iptables or iptables with something else? No, just iptables would be enough. > This is what ive tried... > > on 172.20.128.56 (Red Hat Linux release 7.3) > i issue the command : > iptables -t nat -A OUTPUT -p tcp -m multiport --dports smtp > -j DNAT --to-destination 192.168.12.56 There is no need to use multiport because you only DNAT 1 port : smtp. But that should not be a problem. iptables -t nat -A OUTPUT -p tcp --dports smtp \ -j DNAT --to-destination 192.168.12.56 > now when im on 192.168.12.56 (Red Hat Linux release 9 (Shrike) ) > and do a tcpdump greping for smtp I see connections from 172.20.128.56 > but not exactly sure what its doing.. but what i know, from > 172.20.128.56 I cant make smtp connections out to the internet.. A few obvious tests : Do you see mail coming in from 172.20.128.56 into the queue of 192.168.12.56 ? Is mail from 172.20.128.56 "for the internet" being delivered ? If it's not working, do you have other iptables rules that prohibit this from working ? Gr, Rob ********* DISCLAIMER ********* De informatie in dit E-mail bericht is uitsluitend bestemd voor de geadresseerde. Verstrekking aan en gebruik door anderen is niet toegestaan. Door de elektronische verzending van het bericht kunnen er geen rechten worden ontleend aan de informatie. TTP staat niet in voor de juiste en volledige overbrenging van de inhoud van een verzonden E-mail, noch voor tijdige ontvangst daarvan.
