SMTP Servers

SMTP Servers

This is a technical page describing some of CUIT's mail services, mainly to provide information for campus IT groups.

SMTP is the Simple Mail Transfer Protocol, the standard under which mail is transported on the Internet. Many applications that generate outgoing mail hand it off to an SMTP server that will handle the sometimes complex task of resolving addresses and transporting messages to the destination. CUIT provides SMTP servers for users of the CUIT mail systems (Cyrus and Exchange) and for other servers on campus.


The main SMTP server cluster is If you install a mail program on your computer, you can configure as the SMTP server. Your mail program will send all outbound mail to and then will take care of routing your messages to their destinations. For details see Configuring a Mail Program.

( also handles outbound mail from other systems managed by CUIT, such as Cubmail, Pine, Courseworks, and Columbia's main web servers, and also outbound mail from the CUIT Exchange system to people on other systems.) requires SMTP authentication. The email program you use (see Configuring a Mail Program) will do this for you. requires either TLS encryption (port 587 or 25) or SSL encryption (port 465). TLS to port 587 is preferred. If you are connected through an off-campus service provider you may need to use port 587 to reach

In general is for personal mail sent by individuals using email clients. Mail automatically generated by other kinds of devices or software is usually not handled on You should never store a username and password in software as a way to use Please see the next section about, and if you don't see how to accomplish what you need to do, please contact CUIT.


CUIT provides the system as an SMTP server for a wide array of devices and software that need an SMTP server to send mail. Mail is accepted by without SMTP authentication. The recipient address must end "" or "@" another domain hosted by CUIT. No special permission is needed to use Any host can connect to it.

If you need to relay mail to outside addresses, please contact CUIT to make arrangements.

On the Morningside campus, you are not required to route outgoing mail through an SMTP server run by CUIT. The campus network is open. If your computer has mail transport software, it is allowed to send mail directly to the destination. The SMTP servers are provided for software and devices that need the assistance of a separate SMTP server.


If your application runs on a Linux or Solaris host run by CUIT, use the host's own SMTP server . Configure your application to connect to localhost (literally the word "localhost") at port 587.