Why do users see my domain name when they telnet to the POP3 service?

Question

If someone telnet’s to my POP3 service in addition to the normal "+POP3 Server ready" response there is additional text that includes the domain name of the server so it looks like "+POP3 server ready <389267543@domain.dom>"

I do not want the response to display my domain name, how can I disable this?

Answer

The additional text indicates that you have enabled APOP authentication for the POP3 service.

Normally when users connect to the POP3 Service there username and password are passed across the Internet in clear text. This has the potential of allowing usernames and passwords to be "sniffed" by anyone with the required technology.

The use of APOP authentication to log into the POP3 service means that the usernames and passwords are encrypted prior to being passed over the Internet.

In order for APOP to work, a random string must be created by the server as part of the authentication process. The random string (in this case 389267543@domain.dom) is used for encrypting and exchanging authentication information.

See Also:

• What is APOP authentication?
• Does GMS Mail Support APOP?

Keywords:POP3 POP connection APOP