I am setting up an inbound postfix instance to run on a dmz host.
Its purpose is to accept mail only for specific relay_recipients and to transport them to an internal postfix server. I have demonstrated proof of concept with this * but there is a tweak I cannot easily figure out from the documentation after having tried a few obvious options and reset them. Something basic is missing from my understanding, correcting which would be appreciated. Firstly I need to be sure that nothing entering this server will go out to the internet. All traffic needs to go to the internal smtp box which maildrops stuff into local unix accounts. There is a third box running outbound postfix which is meant to receive outbound mail from clients and have access (in the first place) to my ISPs smarthost. If this seems overengineered, sorry. But I am attempting to learn the details and having things on separate boxes helps. ** Anyway, the issue I am tussling with is that mails destined FOR internal hosts don't resolve locally and instead escape out to my ISP's smarthost where they are picked up with an invalid domain and bounced. I would like to stop this behaviour. ** Actually they don't go to the smarthost. Please see later Which fragments of my various configuration files would be useful to help diagnose this? I observe that mails are escaping directly from this machine and not going to the internal maildrop server nor to the outbound smtp box. In fact, the inbound postfix service is attempting to resolve the internal address as an Internet domain "Diagnostic-Code: X-Postfix; Host or domain name not found. Name service error for name=xxxxx.yyyyy type=AAAA: Host not found". where xxxxx.yyyyy is the internal host I was trying to send to. Anyway this is probably dead simple to someone :-( Thanks in advance DD Croydon, UK * with a previous ISP but have now transferred to another and would like to revive control of inbound mail.
begin:vcard fn:David Denny n:Denny;David email;internet:reply...@daviddenny.co.uk tel;cell:+44 (0) 7834 773 673 version:2.1 end:vcard
