Re: [exim] zone_data expansion oddity

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Author: Philip Hazel
Date:  
To: Derek Buttineau
CC: exim-users
Subject: Re: [exim] zone_data expansion oddity
On Thu, 8 Mar 2007, Derek Buttineau wrote:

> I guess my confusion is with the expansion on manualroute, I would
> think that given:
>
> domainname.com/mx:backup.server.com
>
> That the expansion should put the second manual route entry below the
> lowest preference option returned by DNS. i.e. so you'd have
> something like:
>
> 10 mail.domainname.com
> 20 mail2.domainname.com
> 30 backup.server.com


Yes, I would expect that too, though having put the MX hosts into order
using the preferences, there are then no preference values attached to
things. I would certainly expect the list to be equivalent to

mail.domainname.com:mail2.domainname.com:backup.server.com

/mx is meant to mean "get an MX host list, in order, and stuff it in
here".

> Instead, manulroute appears to be believing that it has a higher
> preference than the lowest preference returned from DNS? At least
> when the local host is removed from the list, everything other than
> the highest preference MX in the entry before it gets removed. So
> basically when it removes backup.server.com it also removes
> mail2.domainname.com from the list.


That certainly doesn't seem right. I'll do some experiments when I get
time, but that won't be right away as I'm diverted onto PCRE work just
at the moment. Maybe towards the end of next week.

However, I did take a brief look at the code earlier today, and it just
chops the list away - doesn't look as if there's any possibility of
removing earlier hosts.

Some tests with -bt and -d might give some clues as to what is
happening. If you can run that with your real domain and host names and
send me the result, it might make it easier to find out whether this is
a problem with Exim.


-- 
Philip Hazel            University of Cambridge Computing Service
Get the Exim 4 book:    http://www.uit.co.uk/exim-book