Many systems that support mail do not support finger or talk. Most non-Unix systems do not have finger and talk facilities. Some Unix systems do not provide network finger or talk support, either for reasons of privacy or CPU conservation.

Also, there are many systems that do not have a direct network connection to mail.sas. It is often possible to send mail to these systems, but it is impossible to finger or talk to them.

Finally, often mail addresses will involve virtual address, called an "MX" (mail exchanger) record. For example, you can send mail to any SAS professor using "person@sas", and this is the address listed in the University phone book. But there is no machine named "sas", and so you cannot establish a talk or finger connection to "sas". This setup allows the SAS department to designate one of their machines as a central mail facility. The actual machine that handles this mail can be changed simply by changing the MX record.

Another example of virtual address occurs when the mail must be translated through a "gateway" to be delivered on some system very different from ours. Examples of this are "a1" and "bitnet" addresses, which instruct our mailer to send the mail to a system that will translate the message into another format, and then send it on to it's final destination.

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Last modified: Tuesday, 28-May-2002 10:03:36 EDT