IETF SMTP Working Group Proposal at smtpng.org

Thu Aug 22 02:52:35 UTC 2002

> Then perhaps you'd like to tell me how we have tens of 
> thousands of users quite happily doing it?
> 
> True, I wouldn't run Hotmail/AOL/EarthLink/etc's MXes off 
> dynamic IPs, but for a home/small biz mail server...
> 
> Oh, and one last thing, when you specify an MX (statically, 
> as you say), you don't put in the IP but rather a name 
> created with A record, so what prevents that A record from 
> being a low-TTL dynamic DNS A record?

Running a mail server off a dynamically assigned dialup *CAN* work, but
it really isn't the thing to do even if you put in a low TTL on the A
record.  Sure it works.  But what about all the messages that will
requeue on remote mail servers and depending on the remote queueing
strategy of the remote mail server, it can take hours before mail could
be re-attempted for delivery.  A dynamically assigned MX box isn't
really the best thing to do.  If you want to do that then you should at
least have a lower preference backup MX that is on 24/7 that will accept
mail on your behalf, and when your server dynamic SMTP server comes
online it can simply do an ETRN to requeue the mail on the backup MX.  

Having one MX on a dynamic DNS mail server is just rude to remote mail
servers that try to deliver mail.  Why should my servers consume more
resources to benefit your customers?

--
Robert Blayzor, BOFH
INOC, LLC
rblayzor at inoc.net

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