Testing your mail server

You can connect to your mail server SMTP service on TCP port 25 using a Telnet or Netcat client and send email to your own account with the following code, where "IP" is the IP address of the server:

telnet IP 25

helo

mail from

rcpt to

enter message here, followed by a full stop on a new line

.

Also, check whether your email server divulges your internal users by supporting the EXPN and VRFY commands (for example, VRFY administrator -> admin@company.com):

' telnet 25

help - does it show EXPN / VRFY to be supported?

EXPN administrator

VRFY admin'

Finally, check if it's possible to send a spoofed email through the email server. For example, SMTP server for domain "company.com" receives an external email from user@company.com. Does your email server drop this email? It should do.