I'm the mail admin at my company (we'll call it FOO.COM) and I have users who are subscribed to LISTSERV mailing lists all over the Internet. One user has left the company and still seems to be subscribed to a list called XYZ@LISTSERV.EXAMPLE.COM. How can I issue a DELETE command for my former user?

LISTSERV servers will accept commands on behalf of users in remote domains if they come from the POSTMAST or MAINT address in that domain. In other words if you have a user joe@foo.com subscribed to the list mentioned, you should be able to issue a "DELETE XYZ joe@foo.com" command to (for instance) LISTSERV@LISTSERV.EXAMPLE.COM as long as the command comes from postmast@foo.com (or maint@foo.com). Note that if you use the former, it has to be "postmast", not "postmaster". If it comes from "postmaster", LISTSERV's default filter catches it and it generates an error. Also note that the hostname must be identical; maint@unix1.foo.com can't issue commands on behalf of joe@foo.com.

If all else fails, you can always write to the generic list owner address for the list (listname-REQUEST@host) or to one of the LISTSERV maintainers, whose address(es) can be found by issuing a RELEASE command to LISTSERV@host, and request that the user be manually removed.