Re: [EXIM] IP spoofing

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Author: Philip Hazel
Date:  
To: Marilyn Davis
CC: exim-users
Subject: Re: [EXIM] IP spoofing
On Thu, 6 May 1999, Marilyn Davis wrote:

> I need to understand IP spoofing. I understand that it is the general
> consensus that it can be done, but how. Don't you have to reveal your
> real IP address to get a message out?


Exim by default blocks incoming calls with "source routed" IP return
addresses. Check out the kill_ip_options and refuse_ip_options settings,
and have a look at the code in smtp_in.c to see how this is implemented.
It's all very hairy. I don't understand it very well and this code got
copied from elsewhere. It is also hard to test!


-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.



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