Sendmail not using FQDN in HELO even though hostname setting is correct.

Jukas · 04-21-2009, 01:42 PM

I'll start with the prefix warning that I've very unfamiliar with sendmail, I personally run and prefer postfix, but my new job uses sendmail for all their mailservers.

We have 3 sendmail servers, (1 primary and 2 that handle outgoing email) and one of them is not sending a FQDN during the HELO process. I've already searched and double checked against every solution I've seen posted so I'm hoping someone can suggest something I may have missed.

Here is what I'm seeing in remote logs when I test email.

Code:

Apr 21 11:27:13 nix postfix/smtpd[22176]: < gandalf.domain.com[xxx.xxx.xxx.xxx]: HELO gandalf

and I'm also seeing bounce back emails containing info like:

Code:

<<< 553 Bogus helo gandalf. <http://unblock.secureserver.net/?ip=>

When I telnet to the server in question port 25 I see the FQDN in the banner

Code:

220 gandalf.domain.com ESMTP Sendmail 8.13.8/8.12.11; Tue, 21 Apr 2009 11:20:59 -0700

/etc/sysconfig/network

Code:

NETWORKING=yes
NETWORKING_IPV6=yes
HOSTNAME=gandalf.domain.com

and both uname -a and the hostname command show the FQDN

/etc/hosts

Code:

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1       gandalf.domain.com gandalf.domainukspellling.com gandalf localhost.localdomain localhost
#::1    localhost6.localdomain6 localhost6
xxx.xxx.xxx.xx      gandalf.domain.com gandalf.domainukspelling.com gandalf

These settings are identical to two other sendmail servers and this is the only one not sending a FQDN in a helo statement. I'd greatly appreciate if anyone could tell me why this server is misbehaving as the primary sysadmin who is very familiar with sendmail is out this week.

bathory · 04-21-2009, 03:39 PM

Check the Dj variable in the working and not working sendmail.cf.
If sendmail cannot identify the domain name (lack of /etc/resolv.conf) you can use:

Code:

Dj$w.domain.com

Jukas · 04-21-2009, 09:39 PM

Thanks for the suggestion but in further testing I narrowed the problem down a php script and not the mail server itself (normal email had the correct ehlo, script generated email didn't). I'm not sure why sendmail allowed it, but a variable of $mail_server = 'gandalf'; was causing the problem. Changing it to $mail_server = 'gandalf.domain.com'; resolved it.