After installing sendmail on ubuntu server 14.04 / 16.04 , I tried sending mail from my php script and it was painfully slow. I thought I had not configured my apache / nginx properly. Me being a noob at this, tried to delete the snapshot and reinstalled with ubuntu 14.04 (earlier one being ubuntu 16). Still the issue persisted. After a lot of googling I kind of figured a solution.
Initially determine the hostname of your server by typing
This will reveal your hostname.
Then go to
sudo vi /etc/hosts
Modify the line with IP to read as
127.0.0.1 localhost localhost.localdomain ashwin
(where “ashwin” is my server’s hostname, you should add your server’s hostname — duh!)
Finally I ran
Answer Y to all the questions asked to rebuild/reload sendmail configuration…
That’s it, Send Mail started working !
Hope this helps for people who struggled with installing a new server in Digital Ocean / AWS and trying to send mail!