Some times we have to see how a remote mail server responding to SMTP connection from our Plesk server. Yes! logs are always there to see whats going on, but using telnet seems very handy to me. It takes less time than scanning logs and lets use of mouse too
Lets use cpanelplesk.com as example here. As my emails from local server to admin@cpanelplesk.com were bouncing and here is what I did.
Open command prompt (Win + R and then in run box, type “cmd” to get the command prompt). Then on command prompt
1. telnet to remove mail server
[box style=’note’] telnet cpanelplesk.com 25 [/box]
The server where cPanelPlesk.com is hosted, returned with following banner.
[box style=’note’]220-xxxx ESMTP Exim 4.82 #2 Wed, 04 Dec 2013 08:18:22 -0600
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail. [/box]
2. At this point, lets tell remote server about the domain you will send email from
[box style=’note’] HELO local.domain-name.com [/box]
[box style=’info’]Although the domain name here should be fully qualified domain name as seen by other devices. But if you do not remember it or it is too long and you are too lazy to type; you can type any FQDN as remote server will believe in what you said. [/box]
Server Response: [box style=’note’] 250 l3.cpanelplesk.com Hello local.domai in-name.com [39.42.10.82] [/box]
3. Now give the senders email address
[box style=’note’] MAIL FROM:my-email@my-domain.com [/box]
It responded with OK, so far so good. seems nothing wrong.
Server Response:
[box style=’note’] 250 OK [/box]
4. Its time to give recepient email
[box style=’note’] RCPT TO:admin@cpanelplesk.com [/box]
and then it refused like
Server Response:
[box style=’note’]550-“JunkMail rejected – (local.domai in-name.com) [39.42.10.82]:64210 is
550 in an RBL, see http://www.spamhaus.org/query/bl?ip=39.42.10.82” [/box]
In 4 steps and less than 30 seconds, I knew exactly why my mail was being rejected. Please comment with your ideas and quicker ways to find out about mail errors.