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Don Rhummy
Asked: 2013-08-23 21:01:34 +0800 CST

sendmail is not delivering messages to recipients

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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 sendmail or mail at the command line both fail. Example:

echo "a message" | sendmail [email protected]
echo "a message" | mail [email protected]

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?

linux

2 Answers

  1. server should be able to connect to other smtp servers

    $ nc -v mta5.am0.yahoodns.net 25
Connection to mta5.am0.yahoodns.net 25 port [tcp/smtp] succeeded!
220 mta1193.mail.ne1.yahoo.com ESMTP YSmtpProxy service ready
^C

    This is how it can look when port 25 is closed for outgoing traffic:

    $ nc -v mta5.am0.yahoodns.net 25
nc: connect to mta5.am0.yahoodns.net port 25 (tcp) failed: Connection timed out

    See if the requests get blocked in your firewalls.

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  2. Have you tried other ports than 25? Most likely you won't have this problem when your not behind a residential ISP. Also when you say thunderbird sends mail, are you authenticating to the server in question? If not then you are probably connecting to another server over a ssl port.

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