Re: [Exim] Sender and receiver verification can cause mail l…

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Author: Philip Hazel
Date:  
To: David Woodhouse
CC: Russell King, exim-users
Subject: Re: [Exim] Sender and receiver verification can cause mail loops.
On Mon, 25 Aug 2003, David Woodhouse wrote:

> > ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1/128 ; fec0::/10 ; fe80::/10 ; ff00::/8
>
> Do you also need to include the real IP address(es) of the host in
> question? And doesn't Exim _already_ have logic to prevent it from
> talking to itself, which can be expected to be correct and could be used
> for this?


The logic that prevents it talking to itself operates by finding the IP
addresses of the running interfaces. These normally include 127.0.0.1.
However, they do not normally include 127.0.0.2, etc.

If you put 127.0.0.1 into ignore_target_hosts, Exim will immediately
bounce anything that resolves to it, behaving as if the address was not
found. If you don't, Exim will conclude there is some configuration
error, and hang on to the message. I'm not sure if it freezes it or not.

However, the only way to deal with 127.anything-else is to use
ignore_target-hosts.


--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book