topic Re: SENDMAIL in Operating System - HP-UX

SENDMAIL

Chris Chaoman — Mon, 18 Dec 2006 09:24:27 GMT

How do I change the destination of an email server on and HP9000 server (hp-ux11.0). I cannot find it in any of the usual comms file, /etc/hosts or in /etc/mail.

Re: SENDMAIL

Geoff Wild — Mon, 18 Dec 2006 09:26:07 GMT

In /etc/mail/sendmail.cf

Set the DS macro (Smart Relay) to the server you want to route mail to/through.

If sendmail is running, then restart it after making the change.

Rgds...Geoff

Re: SENDMAIL

Coolmar — Mon, 18 Dec 2006 09:29:00 GMT

You want to modify the sendmail.cf file and change the mail relay (the line that begins with DS). Change that line to your new email server.

Re: SENDMAIL

Ben Dehner — Wed, 20 Dec 2006 15:05:30 GMT

As pointed out by others, add the DS (Smart Relay) option to /etc/mail/sendmail.cf.

However, a warning, unless your HP-UX system has either no DNS or access to a full internet DNS resolver this won't work.

When sending email to an arbitrary address "someone@domain.com", sendmail will first try to do a DNS resolution on "domain.com" to decide if this is an actual host name or an MX mail record. If this DNS lookup fails then sendmail will queue the message without sending it, regardless of the status of the mail relay. After so many retries, sendmail will give up and never send the message. The only way that I've found to avoid this behavior is to disable DNS lookups in /etc/nsswitch.conf.

I discovered this because our HP servers are behind a firewall and only have access to internal DNS, which consists of servers and DHCP data, and does not resolve arbitrary internet A records or other types of data.