Sendmail... how hard to setup??

[mousematt]

Hi

Am trying to setup sendmail on a default installation of Red Hat Ent. I thought it would 'just work' for sending emails out, this seems not to be the case.

Situation:
We have a linux box that it going to be used for an oracle app, this needs to send emails, only internally to start with, but external in the long run. We have an exchange 5.5 server at the moment that the company uses for email.

After installing a fresh copy of Red Hat on a test box and trying to send to an email address internally nothing happens. Its using our internal DNS as our firewall rule do not let any ports out for this box.

I've tried looking at tutorials on how to set it up, but never thought such a simple thing could be soo hard. I don't think I need too much in depth just enough to send emails from the box. As far as I can tell they all just sit in the /var/spool/mqueue dir.

Help!

 

[lgarner]

The simplest way is probably to set your Exchange server as the smart host.

"DSyour.exchange.server" in sendmail.cf, or
define(`SMART_HOST',`your.exchange.server')

Much more help can be found in the sendmail forum.

 

[mousematt]

I thought that it was that.
Does it have to be a FQDN? or can i use ip?

 

[lgarner]

Either. You'll want to enclose the address in brackets "[]" to prevent MX lookups. I believe that you'll need the brackets for either hostnames or IP addresses in your case.

 

[m4ilm4n]

I could be wrong (like so many times before), but I recall RedHat's sendmail by default is configured to use loopback as the mailer interface; this needs to be changed to the actual network interface before it'll send anything.

 

[lgarner]

You're right. Most of my servers are configured like this:

"O DaemonPortOptions=Port=smtp,Addr=127.0.0.1, Name=MTA"

which allows sendmail to listen only on loopback. This is fine if nothing will ever send mail to this system. Otherwise, change the address to a valid interface address.