-----Original Message-----
From: Dick St.Peters [mailto:stpeters(_at_)NetHeaven(_dot_)com]
Sent: woensdag 14 september 2005 23:33
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: RE: [spf-discuss] solving the forwarding problem
Moreover, /etc/aliases is grossly unsuited for forwarding
even. For one, because data in it is static; which means that
each change of 'hard-coded' forward addresses, for individual aliases,
requires a rebuilt of the entire alias db.
That "entire" alias db is rebuilt by sendmail every time it starts up
anyway.
I surely hope not. :)
Actually, the behavior is determined by:
O AutoRebuildAliases=bool configuration file
define(`confAUTO_REBUILD',bool) m4 configuration
It defaults to 'false'. So, under normal circumstances, sendmail will not
automatically rebuild the aliases database (unless you run newaliases, of
course, or sendmail -bi).
AutoRebuildAliases, when set to 'true', would not just be invoked once, as
the daemon starts, but also every time someone fires up the sendmail
binary (like in a Perl script). That aspect of it alone makes
AutoRebuildAliases practically unworkable in a production environment (as
the overhead for flocking and rebuilding, holding up every other sendmail
process, IS huge).
Unless you have a humongous number of aliases this is a
non-issue
My /etc/aliases is small, of course. Yours, however -- or I should say: if
you use the example of an ISP with several hundred thousand users, all
potentially doing forwarding -- could actually BE humongous.
One big advantage to using aliases is that the "user" part
of a forwarded address doesn't have to be an actual user.
Nobody disputes the advantages of the aliases file, of course. But
pointing an alias to a valid local user, which user has a .forward file,
would accomplish the same and avoid having to rig sendmail in such a
fashion that it is forced to rebuild its aliases database all the time
(including, I premuse, in your case, a forced rebuilt every time a user
changes his or her forwarding address). You are trying to use something
dynamically which was clearly meant to be used statically. Like so many
ill-advised things, it can be done, of course; but ...
- Mark
System Administrator Asarian-host.org
---
"If you were supposed to understand it,
we wouldn't call it code." - FedEx
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