Linux Ask!

Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.

Feb 152012

Sending email using raw SMTP commands


You can send email(s) by connecting to your SMTP server, and using raw SMTP commands.

E.g. assume your SMTP is localhost, listening port 25, enter the commands in bold

# telnet localhost 25
Connected to localhost.localdomain.
Escape character is '^]'.
220 ESMTP Postfix (Ubuntu)
helo localhost
mail from:
250 2.1.0 Ok
rcpt to:
250 2.1.5 Ok
354 End data with .
This is a test mail

250 2.0.0 Ok: queued as BA2FD1DB96
221 2.0.0 Bye
Connection closed by foreign host.

Sep 082011

Show current Postfix queue listing


To show the current Postfix queue, you can try the command "postqueue"

# postqueue -p

-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
BD7E2BF973      972 Sat Aug 27 08:57:54
(connect to[]:25: Connection timed out)
Aug 312011

Debug and verify Postfix configurations


A simple way to debug and verify your Postfix configurations is the use the sendmail command with the -bv flag.


# sendmail -bv

No email will be sent using the above command, it just report after verifying each recipient address. This is very useful for testing the Postfix configurations.