Hi,

For the last few weeks I've been building a network management system using Fedora 11, Nagios and Cacti. Everything is working fine apart from getting Nagios to send email notifications and I believe the problem is with the smtp relay config i've setup.

I started out trying to use sendmail. It worked with my ISP at home but when I moved to the production environment (using a different ISP) I wasn't able to get sendmail to send anything. After reading a few threads I thought i needed to use 'masquerading'. When I tried to set it up I managed to kill sendmail - wasn't even seeing anything in maillog. Tried reinstalling sendmail and sendmail-cf with no joy and didn't know what else to do to revert back to a 'vanilla' config (having not backed up the configs...)

So, I have moved over to postfix and at least getting maillog ok now. I can successfully send mail using telnet. I can get a message through when using the following line:

mailx -s test destaddress@domain.com -r sourceaddress@domain.com

but it sends an email with..

To:
sourceaddress@domain.com; -r@localhost.localdomain; destaddress@domain.com

From:
destaddress@domain.com

Is that the corrrect syntax? If so, why is the -r@ and sourceaddress included in the to field? And why is the From field the destaddress?

When I try to send with:

mailx -s test destaddress@domain.com

I get nothing through. I suspect my ISP is silently dropping it due to the source address being from localhost.locadomain or the like as maillog shows its accepted by the ISP's smtp server. Hence why I tried the -r option.

I'm really confused. Any pointers would be greatly appreciated! I've been battling with this for 4 days now and not sure what else to try. I'm still fairly new to linux and learning curve has been just about vertical so might need spoonfeeding a bit.

Thanks in advance.

Chances are you hit it right on the head, with your ISP dropping it silently. "localhost.localdomain" just screams "SPAMMER" in huge letters, so I'm not surprised it's getting dumped. Look into the masquerade feature, which will let you set your domain to be something 'real', or contact your ISP, and they may be able to offer solutions as well.

I looked at he man page for mailx, and it looks like there is no command line argument for setting the reply address, looks like you use ~R (thats tilde and capital R) at the beginning of a line while composing the message. ie

mailx -s test recipient@domain.com <enter>
~R replyto@domain.com
your message here
.

but the message will still be sent using your.username@your.servers.domain.tld unless you have masquerading

Hope that helps.

P.S.

Acually it looks like you can modify the headers with -a so ..

mailx -a "Reply-To:me@here.org" -a "From:me@here.org" -s "This is the subject" you@there.com

found that little tidbit at http://www.solar1.net/smf/index.php/topic,43.0.html

thanks guys.

@TB0ne

Thanks - at least it sounds like i'm on the right track then. Will have another go at masquerading and if not will spk to the ISP.

@Dangermaus

Thanks for the suggestions. Tried both and with the ~R got an "Unknown tilde escape" and with the header rewriting got an "Reply-to:address@domain.com: No such file or directory"

Will keep pressing on!

have now solved it.. thanks for pointing me in the right direction!!!

All I had to do was change the 'myorigin' variable in main.cf to a valid domain. Mail came straight though with:

mailx -s "Subject" destemailaddress@adomain.com

And for anyone who reads this trying to get Nagios to use postfix..

Have now setup Nagios to use postfix successfully too - just had to change the 'mail' command to 'mailx' in /etc/nagios/objects/commands.cfg and then restart nagios:

validate the config…

nagios -v /etc/nagios/nagios.cfg

reload nagios

/etc/rc.d/init.d/nagios reload