Accessing IMSS Email Via POP

Before deciding to choose the POP protocol for your desktop email program, please read over our Choices for Accessing IMSS Email page. We recommend the IMAP protocol rather than POP if you will be checking your email from multiple computers or multiple programs.

Recommended POP settings

Here are the recommended POP settings. You should check to make sure you have these set in your POP email program:

• POP server = pop-server.its.caltech.edu
• POP account = username@pop-server.its.caltech.edu
• SMTP server = smtp-server.its.caltech.edu
• Reply-To/From address = username@its.caltech.edu or username@caltech.edu depending on your personal preference (see What is My Email Address)
• IMSS requires that mail programs use SSL encryption for sending and receiving mail using the IMSS mail servers. For instruction on configuring your mail client to use SSL encryption, please see our email configuration instructions here.

If users see a "server name does not match server in certificate" error with their POP email programs, please check the email program's settings. The old CCO server names (pop-server.cco.caltech.edu and smtp-server.cco.caltech.edu, which were retired years ago in favor of the IMSS forms) will not work.

Note for Eudora users

Users of Eudora 5.1x (not 5.2 or 6.0) will need to modify your setting for checking email due to poor implementation of SSL support in Eudora 5.1x. Under "Checking Mail", set "Secure Sockets When Receiving" to "Required, Alternate Port". If you're using a version of Eudora lower than 5.1, set "Secure Sockets When Receiving" to "None" if such an option exists.

Under "Sending Mail", set "Secure Sockets When Sending" to "Required, Alternate Port". If you're using a version of Eudora lower than 5.1, set "Secure Sockets When Sending" to "None" if such an option exists.

Upgrading to Eudora 5.2 or 6.0 should resolve these issues. If it does not, set to "Required, Alternate Port" in the newer version of Eudora.

Note for off-campus users

If you are connecting to the Internet via an ISP rather than through the IMSS dialup service or the Caltech-Charter Cablemodem Service, you will need to use your ISP's recommended SMTP server rather than ours, or you will need to configure your email program to use our Authenticated Outgoing Email Service.

Mail Checking Frequency

To keep the mail server responsive and to keep from overloading it with a lot of unneeded checks, we ask that you have your mail program set to check mail no more often than every five or ten minutes.

Additionally, it is a good idea to exit your mail program when you leave for an extended period of time (such as during lunch or for the day). There is no need to have your mail program check your mail every five minutes if you will be gone for several hours.

Special Warnings

Do not use "username@its.caltech.edu" for your "POP Account." The computer its.caltech.edu is an interactive login server, not a mail server. Use "username@pop-server.its.caltech.edu" when telling your mail program which computer to CHECK for mail. (e.g. the "POP Account" setting in Eudora)

Leaving Email on the Server

If you do not need to leave mail on the server, please disable this setting! Having this enabled will cause it to take longer for you to check your mail and places a greater burden on the mail server.

If you do need to use this option (because, for example, you need to check your electronic mail from multiple computers), make sure that you also have 'delete from server after 7 days' (or some number which is suitable for your needs) and 'delete from server when emptied from trash.' For this last option to work properly, you will need to periodically 'empty' the trash in Eudora, or make sure that it is set to empty trash when you quit Eudora before going home in the evening. Similar settings can be made on other mail programs which use POP to access your mail.