We've been happily running an zcs-5.0.16_GA_2921.DEBIAN4.0.20090429055651 for more than a month. Unfortunately a few days ago we started to be unable to receive messages from a couple of domains (which we already whitelisted), we can send messages to them but not recieving them but unfortunately nothing shows up at any of the logs, so we decided to make some external test at Free online network utilities - traceroute, nslookup, automatic whois lookup, ping, finger using the "Email Dossier" tool they offer.
The results show that there's an error stablishing the SMTP connection, which we suspect, could be the root cause of our problem.
The following are the results:
When we perform the same test against an account from a different domain (google mail in this case), the results are the following:
[Contacting mail.dominio.com [18.104.22.168]...]
220 mail1.dominio.com ESMTP Postfix
250-AUTH PLAIN LOGIN
250 2.1.0 Ok
We've been googling and searching on forums for this strange behavior but we've been unable to resolve it.
[Contacting gmail-smtp-in.l.google.com [22.214.171.124]...]
220 mx.google.com ESMTP 21si3356922agb.65
250-mx.google.com at your service, [126.96.36.199]
250 2.1.0 OK 21si3356922agb.65
250 2.1.5 OK 21si3356922agb.65
250 2.1.5 Flushed 21si3356922agb.65
221 2.0.0 closing connection 21si3356922agb.65
Thanks in advance for your kind help, which is much appreciated.