Re: [Exim] Problems caused by localhost entry in Received

Toralf Lund wrote:

> Giuliano Gavazzi wrote:
>
>> At 1:04 pm +0100 2004/01/07, Toralf Lund wrote:
>>
>>> Or perhaps that has nothing to do with it? I've always been under the
>>> impression that the RBL checks would also consult the Received headers,
>>> but I'm beginning to think I've been wrong all along. Are the headers
>>> in any way checked automatically, or just the connecting IP of the SMTP
>>> connection?
>>
>>
>>
>> how would they? Most of the time, if not always, RBL checks are used
>> in the RCPT phase, when the headers are not even known. And it would
>> open the gates for all sort of attacks, imagine a message coming with
>> hundreds of Received: header lines...
>
>
> Yes. The search might easily be limited to a fixed number of entries or
> similar, though.
>
> Obviously, it might be useful if messages are relayed in several steps
> via multiple servers (all of which are "bad", presumably), and only some
> of them are RBL-listed. I don't know how likely that is...

As someone mentioned elsewhere on this list, a special variant of this
situation arises when a servers forwards e-mails for closed accounts to
new addresses, without doing spam checks. You don't want to block
messages from those (you generally welcome what they send), but if you
get these forwarded messages, you would probably like to check the hosts
they originally came from (since the forwarding host didn't.)

- Toralf