[lug] A .forward standoff
Hugh Brown
hugh at math.byu.edu
Tue Jun 14 15:57:14 MDT 2005
I mispoke slightly. The message would die after hitting a maximal hop
count. However you could cause all sorts of messes and manual
intervention may be required to stop the loop.
e.g. in sendmail you could do
user: \user
in the aliases file that would cause the ~user/.forward file to be ignored
until the offending .forward file were fixed.
I asked a colleague and he said that they had a user once with accounts on
three separate servers and would forward mail on each server to the other
two.
e.g. A would forward to B and C; B would forward to A and C; C would
forward to A and B
so it would fork and loop. The user got his mail account disabled. :)
Hugh
On Tue, 14 Jun 2005, Matt Thompson wrote:
> OK, I'm kind of ashamed that I didn't know the answer to a question a
> friend posed me. It seems like something I should know, but I never
> thought about it. I also couldn't find the answer on Google, but that's
> probably due to noise on my searches.
>
> Namely, say you have two mailservers, A and B. In A, you have a .forward
> pointing to B, and in B a .forward to A. What occurs when you send mail
> to one?
>
> I'm sure this situation has some ARPANET-era jargon/USENET name that I
> don't know, and there is probably a paragraph about it in the Sendmail
> doorstop that I overlooked. Heck, maybe one of you even tried it once
> to see.
>
> Wondering away,
> Matt
> --
> The mayfly lives only one day, and sometimes it rains. - Geo. Carlin
> Matt Thompson -- http://ucsub.colorado.edu/~thompsma/
> 440 UCB, Boulder, CO 80309-0440
> JILA A510, 303-492-4662
>
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