I have run into a number of problems getting sendmail to work. None of the solutions I've tried have worked.
First: sendmail was hanging for 60 seconds and then not sending the email.
To solve this, I used suggestions from the web to set my
/etc/hostname to a fully qualified domain name (FQDN) and then put that in
/etc/hosts as well. This did get rid of the hanging, but I still never receieve any emails sent from sendmail.
Second: Installed postfix
This did not fix the issue. Sending an email via
echo "a message" | sendmail firstname.lastname@example.org echo "a message" | mail email@example.com
Both commands return instantly without error, but no email is ever recieved at the gmail account.
I made sure a port was open at 25 in the router as well (although this shouldn't be an issue as Thunderbird can send emails behind the router).
I need to get this working for PHP but cannot figure out where in the many steps from the program to the remote email server it is failing. How would I figure this out?