October 2007
Intermediate to advanced
1308 pages
161h 13m
English
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FEATURE(mailertable)
Database selects new delivery agents V8.1 and later
A mailertable is a database that
maps host.domain names to
special delivery agent and new domain name pairs.
Essentially, it provides a database hook into the
parse rule set
0. Because mailertable follows handling of the
local host, none of the hosts in the $=w ($=w on page 876) will be
looked up with this feature.
New domain names that result from a mailertable lookup are
used for routing but are not reflected in the
headers of messages.
To illustrate, one mapping in a source text file could look like this:
compuserv.com smtp:compuserve.com
The key portion (on the left) must be either a fully qualified host and domain name, such as lady.bcx.com, or a partial domain specification with a leading dot, such as .bcx.com. On the right, the delivery agent name must be separated from the new domain name by a colon. The source text file is converted into a database with the makemap(1) program (The makemap Program on page 370). Beginning with V8.8 sendmail, the host part of the return value can also specify a user:
downhost.com smtp:postmaster@mailhub.our.domain
↑
V8.8 and laterThe host.domain is looked up in
the mailertable
database, and if that
host.domain is found, a
delivery agent, colon, and domain pair are returned.
If the delivery agent (in mailertable) is error, the #error delivery agent is
called. This allows error messages to be put into
the database, as, for example:
badhost error:nohost mail to badhost is prohibited ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.