Truncated, retrying in TCP on Reverse lookup

[Fr34k]

Hello,

As I understand it, there are so many PTRs for that IP address, that DNS will change protocol from UDP to TCP.
So, the message you are getting is informational because of this protocol change.
See the long list of PTRs below.

There should be one and only one PTR for that IP.
Making an SMTP connection to that IP address results in that host saying that it calls itself "minserv.co.za"
Therefore, there should be only on PTR for that IP address with that hostname.

Note that none of the 15 PTRs match this hostname, which is even more silly.

HTH

$ host 196.7.126.38
;; Truncated, retrying in TCP mode.
38.126.7.196.in-addr.arpa domain name pointer www.adventureservices.co.za.
38.126.7.196.in-addr.arpa domain name pointer mail.penoc.org.za.
38.126.7.196.in-addr.arpa domain name pointer mail.travelsense.net.
38.126.7.196.in-addr.arpa domain name pointer mail.mantlemapper.com.
38.126.7.196.in-addr.arpa domain name pointer mail.quintessentia.net.
38.126.7.196.in-addr.arpa domain name pointer mail.datanetsolutions.co.za.
38.126.7.196.in-addr.arpa domain name pointer mail.spatialdimension.co.za.
38.126.7.196.in-addr.arpa domain name pointer mail.spatialwebserver.co.za.
38.126.7.196.in-addr.arpa domain name pointer mail.spatialwebserver.com.
38.126.7.196.in-addr.arpa domain name pointer mail.adventureservices.co.za.
38.126.7.196.in-addr.arpa domain name pointer mail.explorationservices.co.za.
38.126.7.196.in-addr.arpa domain name pointer spa004-1.cust-gw.za.mtnbusiness.net.
38.126.7.196.in-addr.arpa domain name pointer www.thewash.co.za.
38.126.7.196.in-addr.arpa domain name pointer www.gisstaff.co.za.
38.126.7.196.in-addr.arpa domain name pointer www.cheaprentalcars.co.za.

telnet 196.7.126.38 25
Trying 196.7.126.38...
Connected to 196.7.126.38.
Escape character is '^]'.
220 minserv.co.za Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at  Thu, 9 Jul 2009 14:45:58 +0200
rset
q250 2.0.0 Resetting
uit
221 2.0.0 minserv.co.za Service closing transmission channel
Connection closed by foreign host.


 



________________________________
From: Erisan Nyamutenha <Erisan.Nyamutenha at uct.ac.za>
To: bind-users-request at lists.isc.org
Cc: bind-users at isc.org
Sent: Thursday, July 9, 2009 3:34:09 AM
Subject: Truncated, retrying in TCP on Reverse lookup


Hi All

In order for my email server to accept mail from an external source, it does a reverse lookup on the source. I have email coming from a sender whose ip address maps to several hostnames i.e there PTR records pointing to the same IP. when I try to reverse lookup with my own DNS I get the following ;;Truncated, retrying in TCP mode then eventually I get a time out or server can't find 38.126.7.196.in-addr.arpa: SERVFAIL. What could this be?
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