Re: [Exim] exim HELO ack

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Author: Exim Users Mailing List
Date:  
To: Jez Hancock
CC: Exim Users List
Subject: Re: [Exim] exim HELO ack
[ On Wednesday, August 27, 2003 at 12:05:25 (+0100), Jez Hancock wrote: ]
> Subject: Re: [Exim] exim HELO ack
>
> OE6 on win2k appears to send the netbios name in the HELO. On reading
> RFC821 this doesn't appear to break any standard,


Actually that is a direct and total violation of an absolute "MUST"
requirement in RFC 1123 section 5.2.5. Note the year on RFC 1123. Note
the fact that RFC 1123 is the core and foundation of all Internet
requirements.

All SMTP clients "MUST" use their fully qualified host domain name (or
their literal IP address) as the parameter for the SMTP greeting command.

> Personally I'm not overwhelmed by spammers or other abusers who misuse the
> HELO/EHLO command


You'd be surprised if you really turned on proper validation as I
described just how much spam would be stopped by that one very simple
test alone.

> and I can't justify denying or dropping clients based
> solely on the fact that they don't use a FQDN or even an address literal
> in their HELO/EHLO - a lot of my users use OE which appears to not adhere
> to this anyway.


Wait a minute here!

1. you don't have to force your own broken local clients to obey.

2. you can whitelist lazy/ignorant/idiots like hotmail.com.

--
                        Greg A. Woods


+1 416 218-0098                  VE3TCP            RoboHack <woods@???>
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