Verizon problems - what else is new
Mark_Andrews at isc.org
Mark_Andrews at isc.org
Tue Jan 13 22:19:04 UTC 2004
> Verizon has implemented something new.
>
> My client tells me that Verizon tells them:
>
> <snip>
> Now, I don't totally understand all this, but what they're saying is
> that
> when they try to authenticate the domain that is sending the email
> (which
> should be raq41.provincetowndesign.com) the PTR record's IP Address is
> 65.58.240.193...and dnssys.com reports a different IP Address (or
> something
> like that).
> </snip>
% dig9 -x 65.58.240.193 +short
193.128-255.240.58.65.in-addr.arpa.
www.dnssys.com.
% dig9 +short www.dnssys.com
65.58.240.155
%
The reverse and forward records do not match.
If you start with the IP address. Lookup the PTR to get a
name. Look up the addresses of that name. If the original
address in not is the set of addresses returned in the final
lookup there is a mis-match.
Some sites refuse to accept mail from IP addresses where
the above test fails in the mistaken belief that it stops
spam.
All it really indicates is a inconsistancy in the DNS.
> I've checked our forward/reverse DNS.
>
> The email is coming from raq41.provincetowndesign.com. Dig gives us
> 65.58.240.200.
>
> But doing dig on 200.240.58.65.in-addr.arpa and doing nslookup on
> 65.58.240.200 gives us a cname and a ptr, and only the cname appears to
> be for the exact IP#.
Try "dig -x 65.58.240.200 ptr". BIND 8 (and older) digs default
to type "*" (any) with -x and "*" queries do not result in the
CNAME being followed. If you change the query type to "ptr" it
will be followed. Dig from BIND 9 defaults to "ptr".
The CNAME you are seeing is that from a RFC 2317 style delegation.
% dig9 -x 65.58.240.200 +short
200.128-255.240.58.65.in-addr.arpa.
raq41.provincetowndesign.com.
% dig9 +short raq41.provincetowndesign.com
65.58.240.200
%
> I'm guessing my upstream (who does reverse dns for me) is doing
> something wrong, but I can't tell what.
>
> If you have a moment, please do some lookups and let me know what you
> think.
>
> Thanks.
>
> Jeff
> --
> Jeff Lasman, nobaloney.net, P. O. Box 52672, Riverside, CA 92517 US
> Professional Internet Services & Support / Consulting / Colocation
> Our blists address used on lists is for list email only
> Phone +1 909 324-9706, or see: "http://www.nobaloney.net/contactus.html"
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at isc.org
More information about the bind-users
mailing list