After a week of being very busy with other things, I wanted to take a few minutes and check on my blog only to be greeted by “Site cannot be reached.” SSH’ing into the site resulted in a similar response. So what happened?

A week prior, I decided that I needed to migrate Sendmail over to Postfix. That part was easy enough – the Postfix install removed Sendmail and after a few quick changes everything was up and running. Or was it?

At some point, either Linode or I rebooted the server. Suddenly the IPv4 interfaces would refuse to load. The logs show one error that repeats:

ifup /etc/network/if-up.d/sendmail Can’t open /usr/share/sendmail/dynamic

It seems that wonderful removal process didn’t remove the one part of the network upstart job which called to Sendmail. This caused the whole process to die. Thankfully the fix was simple:

apt-get –purge remove sendmail sendmail-base sendmail-bin
sudo /etc/init.d/networking restart

Sometimes, I’m my own worst enemy…

Reference: https://www.linuxquestions.org/questions/ubuntu-63/sendmail-not-letting-me-restart-networking-service-667894/