I'm a bit confused about the e-mail config on linux...
Basically I want to be able to send an email from linux using mutt and change the cron notify to an external email address.

When I try to send a mail I get 'Unable to relay for <recipient address>'

We have MS exchange e-mail servers so I want my linux box to be able to send an e-mail out via the exchange boxes.

I thought that if you set up a mail server to require authentication then it basically stops anyone other than authenticed users from sending email to your network - it wouldnt accept mail from hotmail.com for example. So I should not have to authenticate should I? I should just be able to specify the smtp server on the linux box somewhere and I should be able to send mail.

I'm not worried about recieving mail, just want to send out notifications for cron jobs etc.

I have our exchange server in dnl define(`SMART_HOST', in the sendmail.mc and have done the m4 make, restarted sendmail since.

As I said, bit confused about it overall, might be trying to approach this entirely the wrong way :-)

hi,

for mail server. sendmail is out of date.
use Qmail.
Complete Qmail installation guide.
www.qmailrocks.org

Qmail isn't actually open source, and so no Linux vendor can or will support it. The two main open source alternatives to Sendmail are Postfix and Exim. Postfix is more popular, and Exim is more flexible, but both are well-documented (and use human-readable config files!).

"Smart host" is the correct term, and you've doing the right thing. Your Exchange systems may require authentication before they will pass the mail, though - the best things to do is to check with your Exchange administrators.