O'Reilly logo

Sendmail, 3rd Edition by Bryan Costales

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Name

FEATURE(virtusertable)

Synopsis

A virtusertable is a database that maps virtual (possibly nonexistent) domains into new addresses. Essentially, it gives you a database hook into the early part of the parse rule set 0. Note that this only reroutes delivery. It does not change mail headers.

By way of example, consider one mapping in a source text file:

info@stuff.for.sale.com       bob
info@stuff.wanted.com         hans@remote.host
info@auction.com              hans@remote.host
@fictional.com                user@another.host

The key portion (on the left) must be either a full address (user, host, and domain name), as in the first two lines, or an address without a host part (just a domain), as in the third line, or an address with the user part missing, as in the last line. This source text file is converted into a database with the makemap(1) program (Section 5.5).

The first three lines illustrate a full address for the key. The first line will be delivered to a local user (bob), the second and third to a remote user (hans@remote.host). The fourth line shows how all mail to a virtual domain (fictional.com) can be delivered to a single address, regardless of the user part.

Note that sendmail does multiple lookups, so one line can reference another. The following, for example, will work:

info@stuff.for.sale.com       forsale@fictional.com
@fictional.com                user@another.host

Here, mail to info@stuff.for.sale.com will be delivered to user@another.host.

Also note that virtual hosts, just like real hosts, need to belong to class w ($=w ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required