[Dnsmasq-discuss] Enabling Reverse Lookup In A Live Environment

Jason Wallace jason.wallace at myrealbox.com
Fri Nov 14 01:21:30 GMT 2008


    I am currently running dnsmasq for a small lan as a dhcp and dns server.  I recently switched upstream providers and my new provider seems unable to do the reverse lookups for me.  So, much of the email from my domain is getting bounced because the reverse lookup doesn't succeed.  I would like to set up dnsmasq to answer reverse lookup requests, but I don't quite know how to begin.  Here's some info regarding my network:

1.  The network is "NAT"ted, by the machine that runs dnsmasq.
2.  Inside my lan, my domain, xxxx.com, resolves to a local machine (email server),, for instance.
3.  Outside my lan, dnsmasq would have to answer that the global IP,, resolves to my domain name, xxxx.com.
4.  Right now, my network does not answer DNS requests from outside. 
5.  My domain registrar is also doing the forward DNS on their name servers.
6.  My upstream provider (ISP) is not the domain registrar.

All the details above are fabricated, of course.

Question 1:  Will this even work?  How can I tell if my NAT machine is even receiving the reverse dns requests?

Question 2:  Assuming that my machine is interrogated for reverse DNS, how do I implement it in dnsmasq in a live environment minimizing downtime.  Especially regarding that the domain name resolves one way to my lan and another way (in reverse) to the internet?

Jason Wallace

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