Hi All, I'm running Postfix on OpenBSD and have multiple external links on the same box. I want outgoing smtp connections to be routed to ext_if2, but the rest to ext_if1. To achieve this, default route being ext_if1, I tried a couple of things:
pass out log quick route-to ($ext_if2 $ext_gw2) \ proto tcp to any port smtp user _postfix keep state Looking at pflog, this rule really tries to send packets to ($ext_if2 $ext_gw2), but e-mails cannot be relayed (for some reason pflog reports that it duplicates the packets). I wasn't too hopeful anyway per the description of route-to in pf faq. Then again, this rule summarizes what I'm trying to achieve. (Or is this rule supposed to work, and I'm doing something else wrong?) The other option would be to set the default route to ($ext_if2 $ext_gw2), but that's not what I want. I use route-to successfully for connections originating behind the firewall, but smtp connections originate from the box itself. I use reply-to successfully too. In short, I need something like destination-port-based routing for multiple links. The situation is not specific to smtp port or Postfix, I'd like to achieve the same for any port I wish. What are my options? What can I do in such a case? (Since I'm out of ideas and since route-to works fine, my only option otherwise seems like placing another OpenBSD/pf in front of this box, which I believe would be ugly.) This is also related to a previous thread on a similar topic. I would appreciate any help. Thanks,
