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Re: Minor is. It's not a pardigm change

2008-03-30 23:07:02

John C Klensin wrote:
If one were designing the architecture de novo today, in today's 
environment, there would be a strong case for "no MX default", but the 
sort of situation Carl mentions would also make a strong case for 
separate "MX-forward-path" and "MX-reverse-path" (bounces) records.

I dunno. I get leery any time the specs assume that the guy running the 
mail server and the guy running the DNS server are on speaking terms. 
I've seen too many cases (even in smallish companies) where the 
corporate mail server and DNS were run by one department, but web and 
E-mail aware applications were run by another. Typically, the latter 
group would be pre-allocated a "pool" of hostnames, A records, and PTR 
records. When they added a new server, they'd just grab the next name 
and number from the pool. If they had to differentiate in advance which 
machines sent mail, and throw MX records into the mix too, they'd never 

        What they are being allocated today is a A record, PTR and
        MX implicit. 

        They can achieve exactly the same thing by requesting a
        pool of A, PTR and MX records.

        Or eventually when they add a new host they will just get
        the next KEY record from the pool and the host will add the
        AAAA, A, MX ("0 ." by default) and PTR records for itself
        using the KEY record and SIG(0) for the forward records and
        TCP based athentication for the reverse record.  6to4 reverse
        already uses TCP based authentication so the later is not
        a big stretch of the imagination.


Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews(_at_)isc(_dot_)org