Underscores in host names

Brad Knowles brad at stop.mail-abuse.org
Thu May 19 09:45:09 UTC 2005


At 6:10 PM -0700 2005-05-18, william(at)elan.net wrote:

>  The only reason it has not been discussed more actively is that no
>  TLD operator has yet come forward and said that they are going to use
>  TLD host for emails, but as soon as one does this would have to be
>  accommodated and quickly (otherwise it will remain as an open issue
>  for future update to SMTP - probably RFC4821 if this numbering
>  continues :)

	Check Guinea-Bissau for .gw.  This has been a source of heartburn 
for many years.  Any site that has a mail gateway system and uses 
unqualified hostnames is at risk, because mail to "fred at gw" could 
legitimately be interpreted two different ways, and mail could be 
mis-directed.

	I did some consulting at a major wall street trading firm that 
had this problem, and the only reason we ever found out that 
something truly bizarre was going on was because we were getting back 
these bounces which we couldn't explain, because we knew for sure 
that the user portion was legitimate.  Then we started looking closer 
at where the bounces were actually coming from.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.



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