Minimal setup for sendmail to send outgoing email only?

Question

I run a simple server that I administrate remotely, and I need it to be able to send an email to my personal email address every time an error occurs. With the default setup on Ubuntu, sendmail just accumulates emails in /var/spool/mail that are to be sent locally, but I need it to go to an external email.

The tutorials I've found all talk about setting up postfix/sendmail as a full-fledged email server, but I just need outgoing only, no external logins. Is there an easy way to do this?

Solution 1

You should also pay attention if you need a relay host and define it (DSmy.relay.host)

Solution 2

Assuming you are actually using postfix.

I would run dpkg-reconfigure postfix and select the "internet site" or "internet site with smarthost" (if you want to send the mail through a smarthost) option as a starting point. This will enable you to send mail to and receive mail from the internet.

If you don't want the box to be able to receive mail then I would suggest configuring the SMTP server to listen on localhost only. See https://superuser.com/a/430329/506601

Solution 3

Check that your server is open to the world in port 25 ( outgoing only). And the dns is configured correctly. You are not suppose to do anything to sendmail for sending outgoing mails.

Solution 4

Maybe nullmailer is for you.

Solution 5

Here are some details on how to setup sendmail for Outgoing Only

Also on this page

I modified these steps from what is listed on the website for centos/Amazon Linux.

Here are the steps:

you may also need to install sendmail-cf
# yum install sendmail-cf

# cd /etc/mail
# nano local-host-names
add new line: localhost
save the file and quit the editor

# make
# nano sendmail.mc
add these lines above the other FEATURE lines near the top of the file:
MASQUERADE_AS(`yourdomain.com')dnl
FEATURE(masquerade_envelope)
save the file and quit the editor

# m4 sendmail.mc > temp.cf
# mv temp.cf sendmail.cf
# make
# /etc/rc.d/init.d/sendmail restart

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Comments

[Peter Green]

I used to use nullmailer, but moved away from it due to bugs.debian.org/cgi-bin/bugreport.cgi?bug=329192 it was partially but not completely fixed.