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Re: what to say on timeout?

2004-01-07 23:51:51


On 1/7/2004 12:09 PM, Richard O. Hammer wrote:

I would argue that a new reply code be assigned to SMTP server timeout.

I would argue against using 421 because that means something 
distinctly different.  A well programmed SMTP client which notices 
that it has received a 421 may conclude "Service not available" 
(reference Sections 4.2.2, 4.2.3), may therefore add the host to "a 
list of hosts it cannot reach" (reference Section 4.5.4.1), and may 
erroneously postpone further attempts to reach that host.

I read 4.5.4.1 to mean that the message should be requed and the host
should be retried since a transient error occurred during the session, not
a reachability error that prevented the session from being established.

Using an enhanced status code could be useful, but that does not need to
be specified in 2821bis. ESN codes 4.4.1 and 4.4.2 both seem applicable,
although a more-specific ESN would probably be more useful. A separate
document describing such a code would also serve as a useful vehicle for
explicitly describing the appropriate behavior. So, it may be that a
minimal clarification to 2821 can get us most of the way there and a
separate document can get us the whole way.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/


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