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From: jim@hwcs.UUCP (Jim Crammond)
Newsgroups: net.mail
Subject: Re: a common sendmail.cf bug
Message-ID: <611@hwcs.UUCP>
Date: Thu, 12-Sep-85 07:20:46 EDT
Article-I.D.: hwcs.611
Posted: Thu Sep 12 07:20:46 1985
Date-Received: Wed, 18-Sep-85 05:45:53 EDT
References: <9600010@uiucdcsb> <10306@ucbvax.ARPA>
Reply-To: jim@hwcs.UUCP (Jim Crammond)
Organization: Computer Sci., Heriot-Watt U., Scotland
Lines: 36

In article <10306@ucbvax.ARPA> fair@ucbvax.ARPA (Erik E. Fair) writes:
>This is not a bug; you should be using route address to begin with
>(messy as they are). The percent syntax is a non-standard hack, 

Sendmail has severe problems translating addresses into rfc822 style
because of commas and angle brackets.

Firstly, note that percent syntax is not a non-standard hack. It is
defined in the UK's Greybook protocol and I think is used in CSNET too.
Thus gateways from these networks to real 822 sites should convert address
styles.  Unfortunately sendmail gets into a bit of a mess over this when
converting headers because a proper translation should look like:

user%domain1%domain2@domain3  =>  user <@domain3,@domain2:user@domain1>

Sendmail only passes what's inside the angle brackets to the rulesets.
It rewrites this bit then restores the rest of header (including angle
brackets, if any).

So, if you add angle brackets within the rulesets then the final address
in the headers could have 2 layers of angle brackets - this causes the next
mailer down the line to barf since you can't nest angle brackets!

If you don't add angle brackets then you could break the address into two:
"@domain3,@domain2:user@domain1"  becomes two comma separated addresses
"@domain3" and "@domain2:user@domain1". This usually means the next mailer
down the line sends the mail to domain2 okay (not necessarily via domain3)
and also returns the message with "@domain3... User Unknown".


Fortunately, most real gateways between percent and 822 sites use MMDF....
-- 
-------------
-Jim Crammond		JANET:	jim@UK.AC.hw.cs
			UUCP:	jim@hwcs.uucp  or  ..!ukc!hwcs!jim
			ARPA:	jim@cs.hw.ac.uk


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