A telnet client is a handy testing tool for testing connectivity between servers. Today I needed to test an SMTP server connection from a linux environment so I wrote the following script. You could use the same technique manually to do the same thing as long as your have access to a telnet client.

Usage

The script takes three parameters: the smtp server url, the sender address and the recipient address.

#!/usr/bin/env bash
	(echo HELO
	 sleep 10
	 echo MAIL FROM\:$2
	 sleep 10
	 echo RCPT TO\:$3
	 sleep 10
	 echo DATA
	 sleep 10
	 echo .
	 sleep 10
	 echo QUIT) | telnet $1 25