Hi all,

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)
EHLO myhost
250-myhost.mydomain.gr Hello localhost [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-EXPN
250-VERB
250-8BITMIME
250-SIZE 4096000
250-DSN
250-ONEX
250-ETRN
250-XUSR
250 HELP
MAIL FROM: user@mydomain.gr
250 2.1.0 user@mydomain.gr... Sender ok
RCPT TO: otheruser@otherdomain.gr
250 2.1.5 otheruser@otherdomain.gr... Recipient ok
DATA
354 Enter mail, end with "." on a line by itself
TEST
TEST
.
=========> 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?

Cheers!
:p

Hello,

Your version of Sendmail is rather old -- I am running 8.12.8-9.90 on my machine. Granted, sendmail is not something to just run out and patch, but you should consider it, as I think they found big security problems in 8.11

I would start there.

Christian

this could be a problem with DNS reverse lookups...or it could be a hosts issue...use tcpdump or a packet sniffer for DNS tshooting. For hosts, ensure that your host is linked in your /etc/hosts file (or equivilent).

the way i solved my sendmail the first time was to add 'lookup file bind' in my resolv.conf file (slackware Linux). However, this was only a temporary fix as it slowed again later. Complete resolution did not happen until I installed postfix. Good thing about postfix was it is compatible with just about all sendmail functions so I was rolling right away.