Dear Ken, On Thu, Jan 12, 2012 at 01:05:10PM -0500, Kenneth Gober wrote: > On Tue, Jan 10, 2012 at 1:41 PM, Dr.-Ing. Torsten Finke < > torsten.fi...@igh-essen.com> wrote: > > > On my firewall I have TWO different internet connections. It is simple to > > forward - for instance ssh - > > from both connections to an internal machine. Now this machine answers and > > the > > firewall sends the reply back. How can I force the firewall to send the > > reply > > over exactly that interface the request came in? The problem is that the > > client anywhere on the internet expects the answer from the very address it > > had contacted. If now the reply comes from another address, it will get > > lost. > > > > I am doing this using OpenBSD 4.6, without any apparent problems, using the > following syntax: > > pass in log quick on $pri inet proto tcp to ($pri) port 1194 > pass in log quick on $sec reply-to $sec inet proto tcp to ($sec) port 1194
great! I thought it to this simple. May I ask about your routing? For this to work I consider you should have multipath routing. You call your interfaces $pri and $sec. Are they configured differently? The pf.conf(5) man page says, that "reply-to is useful only in rules that create state". Do you manage state by some other rule before? > Unfortunately, the pf.conf syntax has changed since v4.6 and while I do > plan to upgrade my > own firewall to v5.0 (I've bought the CD already) I haven't yet had time to > perform the upgrade. > As a result, I haven't worked out what the equivalent 'modern' syntax would > be, but you might > be able to get some hints from what I'm using in v4.6. Yes! Concerning syntax I did some tests. The follwing rule is syntactically correct (in the sense that it is accepted by pf, at least on 4.8): pass in on $vpn_if inet proto udp from any to any port 1194 \ keep state reply-to ( $vpn_if $vpn_if:peer ) I think this can be done simpler. Thanks a lot for your advice Torsten > > -ken -- ------------------------------------------------------------------------ Dr.-Ing. Torsten Finke torsten.fi...@igh-essen.com Tel.: +49 201 / 36014-17 Ingenieurgemeinschaft IgH Gesellschaft f|r Ingenieurleistungen mbH Heinz-Bdcker-Str. 34 D-45356 Essen Amtsgericht Essen HRB 11500 USt-Id.-Nr.: DE 174 626 722 Geschdftsf|hrung: - Dr.-Ing. S. Rotthduser, - Dr.-Ing. T. Finke, - Dr.-Ing. W. Hagemeister Tel.: +49 201 / 360-14-0 http://www.igh-essen.com ------------------------------------------------------------------------