DNS Server goofiness

Mike Hoskins (michoski) michoski at cisco.com
Thu Feb 4 21:01:12 UTC 2016

Do you really want to return RFC1918 to the Internet?  Not the end of the world, but some consider it unnecessary information disclosure.  :-)

I've seen this on various WAN/fw/router used at home over the years (arris, cisco, linksys, etc) and unlike the commands Reindal shared which are geared more toward SOHO/enterprise (e.g. IOS) you might need to look around your "gateway" settings.  This can have various names, but is usually a check-box under lan/wan/firewall/advanced settings vs basic setup.  Hopefully you can find something there which will be obvious (googling for the manual for your exact device should help).


From: <bind-users-bounces at lists.isc.org<mailto:bind-users-bounces at lists.isc.org>> on behalf of David Hornsby <davidh at carolinaky.com<mailto:davidh at carolinaky.com>>
Date: Thursday, February 4, 2016 at 3:29 PM
To: "bind-users at lists.isc.org<mailto:bind-users at lists.isc.org>" <bind-users at lists.isc.org<mailto:bind-users at lists.isc.org>>
Subject: DNS Server goofiness

I am having an issue with an authoritative dns server that sits behind a nat. I have replicated this problem on two different servers on different versions of bind which is why I am now perplexed. In the zone file the LAN address of the server has an A record. When the server is queried directly from the LAN, the server replies with its LAN address. Just as expected. However when the record is queried from through the fw the server replies with its public ip address. Which I can only guess it's getting by doing a reverse on the NS record that pointed it there in the first place??? This only happens on the record with an IP address which matches the server's lan address.

$nslookup dc01

Name: dc01.home.carolinaky.com

$ nslookup dc01

Non-authoritative answer:
Name: dc01.home.carolinaky.com

I'm confused.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/bind-users/attachments/20160204/fa437498/attachment.html>

More information about the bind-users mailing list