nanog mailing list archives

RE: fixing insecure email infrastructure (was: Re: [eweek article] Window of "anonymity" when domain exists, whois not updated yet)


From: "Joseph Johnson" <joseph.johnson () hostwaycorp com>
Date: Thu, 13 Jan 2005 09:05:09 -0600


Basically a call to operators to adopt a consistent forward and
reverse DNS naming pattern for their mailservers, static IP netblocks,
dynamic IP netblocks etc.

...and to ISPs to facilitate the process by supporting their users who
want to run mail servers, and helping the rest of us use such techniques
to quarantine the spew from zombies and less conscientious mail admins.

I'm always willing to be educated on why it is impossible for any given
ISP to maintain an in-addr.arpa zone with PTRs for their customers who
wish to be treated like real admins, as opposed to casual consumer-grade
users with dynamically assigned addresses.


The problem is it is easier to set it up with a single standard
4-3-2-1.dialup.xyzisp.com then to change the IN-ADDR to mail.customer2.com.
I only have an rDNS entry on the box at home because I used to work for the
ISP.  It's still there only because they probably haven't noticed, and will
not until I draw attention to it or I give up the space if I cancel service.

Still, it took me 3 minutes to put rDNS on most of 7 of 16 in my /28.  It
existed in their provisioning system to do it, but no one knew how.  We
couldn't even market it as a service, because it "didn't exist" in the
system.  I can't imagine, though, SBC being able to cope with tens of
thousands of small business DSL accounts suddenly needing rDNS on their
static IP's.

Another question, though, is how they handle IN-ADDR and swip for dedicated
circuits.  If they can do it for a T1 customer, can they do it for a DSL
customer?  Maybe an online form the customer can maintain?  Lord knows that
would be better then trying to call their DSL tech support . . . 


Joe Johnson


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