I am having a problem with Sendmail on HP-UX. I am using it to relay e-mails from an application to external mail servers.
The problem exists when the remote mail server is slow in its responses. Here is a sample of the SMTP conversation between my application and sendmail, with some comments:
220 myhost.mydomain.gr ESMTP Sendmail 8.11.1/8.11.1; Wed, 17 Nov 2004 13:13:17 +0200 (EET)
250-myhost.mydomain.gr Hello localhost [127.0.0.1], pleased to meet you
MAIL FROM: firstname.lastname@example.org
250 2.1.0 email@example.com... Sender ok
RCPT TO: firstname.lastname@example.org
250 2.1.5 email@example.com... Recipient ok
354 Enter mail, end with "." on a line by itself
=========> Here is where the response is very slow. The thing is that the message has been accepted by sendmail, but because "Message accepted for delivery" has not been received yet, my application thinks that there is some problem, and resends the e-mail (the application has a configurable timeout to wait, which I increased - it solved the problem with most e-mail servers, but not with all of them). This results in multiple e-mails being sent when only 1 was intended to.
250 2.0.0 iAHBDSQ08422 Message accepted for delivery
Does it ring any bells to anyone? Is there any way to have sendmail send the confirmation "message accepted..." so that my application behaves better?