Sendmail problem

Linux sendmail senting problem

[peter_lua]

Hi to the expert of sendmail.
I recently got some problem with the sendmail application.
Some users in my company supposed to receive some e-mail from external company but they did not receive any. Have checked on the log but there are no error found. Can anyone guide me on how to troubleshoot this problem?

Another thing is I have just created a new account with aliases to external e-mail. The mail can be sent to all the aliases but external e-mail cannot sent to this new e-mail account. there is an verification error on the system log which says unable to resolve dns and etc.

Thanks in advance to all who can help.

[sunveria]

Hi too...
I'm not an expert but I'm interested with your problem.

So, Your sendmail was able to send and receive email before?

Have you check your DNS yet?
May be that's a DNS problem.

[RonPK]

A bit late for a reply, but here's how to fake a sendmail/smtp-session:

* telnet into your mail server:

telnet mail.yourcompany.com 25

* issue the following set of commands, and see what happens:

helo yourcompany.com

// you should be greeted with a warm welcome

mail from: <[e-mail]>

// server should reply something like 'Sender OK'

rcpt to: <[e-mail]>

// server should reply something like 'Recipient OK'

quit

// end the telnet session

These are (some of) the commands that are used when mail servers communicate with each other. This technique may provide useful information for debugging purposes. If all goes well, your colleagues who complain about not receiving mail may be wrong: either they *have* received the mail, or the mail has *not* been sent. But there could also be a DNS issue, although in that case it would be unlikely that some mails get through and others don't.