it seems, that gwia 2014 R2 send mail is not RFC complaint for handshaking postscreen pipelining with another smtp-server.
(postfix postscreen is an antispam solution)
Because of this, we could not send emails to such smtp-servers and got always this error-message:
450 4.3.2 Service currently unavailable

postmaster of such postfix-server analyzed protocol traffic:
The reason of rejection - your server sent:
"QUIT\r\n"
and then before receiving response:
"\000"
The null sign shouldn't be sent before "221 2.0.0 Bye".
It is probably a bug in implementation of your SMTP server

He could whitelist our mail-domain to disable this kind of check, but it would be better gwia could handle this.

by: joerg g. | over a year ago | Agents