Written by my colleague Marshall J. Krinitz Original Documentation Found Here.
GNU/Linux ?
Scope: Set up a general-purpose internetwork routing facility that supports SMTP.
Dependencies
Install these packages first, per your OS:
| CentOS | Ubuntu |
|---|---|
yum install | apt-get install |
| sendmail-cf | sendmail-cf |
| mailutils | mailutils |
| sendmail | sendmail |
Disable Sendmail daemon
Improve Sendmail security by turning it off.
systemctl stop sendmail
systemctl disable sendmail
Preflight checks
You’ll need these.
- Check for required files:
ls /etc/mail/submit.*
should yield:
/etc/mail/submit.cf
/etc/mail/submit.mc
- Check for
m4processor:
which m4
should yield:
/usr/bin/m4
Build submit.cf file
The secret sauce.
- Backup
submit.cf:
cp -v /etc/mail/submit.cf /etc/mail/submit.cf.bak
- Create
mysubmit.mcmacro configuration file by copying default macro configuration file:
cp -v submit.mc mysubmit.mc
- Modify
mysubmit.mc,
replacing:
[127.0.0.1]
with:
mailhost
on the msp line so that is looks like this:
FEATURE(`msp', `mailhost')dnl`
- Commit your change (from
/etc/mail):
m4 mysubmit.mc > /etc/mail/submit.cf
Modify /etc/hosts file
More goodness.
- List the host’s IP & hostname, e.g.:
127.0.1.1 foobar.psych.nyu.edu foobar foo
- List an SMTP client (choose 1):
216.165.47.33 smtp.nyu.edu nyu mailhost
128.122.112.26 calaf.cns.nyu.edu calaf mailhost