Is it possible to override a single domain name using dnsmasq

dnsmasqdomain-name-systemroutingspoofing

I have a server application that I'm running two instances of, production and development, namely:

prod.example.com (10.0.0.1)
dev.example.com (10.0.0.2)

A third-party has written a client application which has been hardcoded to point to prod.example.com. But, I want those requests to go to the dev.example.com server and I don't have access to the third-party source code.

I do have access (temporarily) to the LAN that the client and server are running on so I can use dnsmasq to resolve prod.example.com to 10.0.0.2, at which point my work here is done and the client application will be (unknowingly) talking to the development server (or so I thought).

I've gotten as far as adding the following config to dnsmasq.conf..

address=/prod.example.com/10.0.0.2

..which does work, but it has the side-effect of preventing all other domains from resolving.

How can I have my cake and eat it?

Best Answer

Add this line to /etc/dnsmasq.conf:

addn-hosts=/etc/dnsmasq.hosts

Then insert your domain names into /etc/dnsmasq.hosts:

10.0.0.1  prod.example.com.
10.0.0.2  dev.example.com.

Don't forget the period at the end of the domain name. It marks it as a TLD, not a local hostname.

As always after configuration changes, restart dnsmasq:

sudo service dnsmasq restart

Related Solutions

DNSMasq – Setting Up DNSMasq for a Local Network

Refer to the DNSmasq documentation, especially the dnsmasq manpage and sample configuration file. The local keyword tells DNSmasq to perform those domain lookups with local data. This affects requests send to DNSmasq for foo.localnet and bar.localnet, for example. I don't think this is what you want.

# Add local-only domains here, queries in these domains are answered
# from /etc/hosts or DHCP only.
local=/localnet/

To force host/subdomain lookups to resolve to a specific address, you'd probably want to use the address keyword. The second example below should allow web1.devbox and web2.devbox and web73872.devbox to all resolve to the address specified.

# Add domains which you want to force to an IP address here.
# The example below send any host in doubleclick.net to a local
# webserver.
address=/doubleclick.net/127.0.0.1

# for your example
address=/devbox/192.168.3.99

I use DNSmasq at home to handle simple DNS stuff for my LAN; in that case, local and the associated domain and expand-hosts keywords are appropriate. The DNSmasq server is my primary nameserver, so all requests go through it; any nonlocal addresses are passed back to the ISP's nameserver. You might consider that configuration if possible.

Using dnsmasq for accessing multiple nameservers assigned by DHCP

If you install resolvconf, NetworkManager will use it instead of writing /etc/resolv.conf directly. The DNS servers from NM can then be found in /var/run/resolvconf/interface/NetworkManager.

dnsmasq is sending all queries to 10.111.1.1 because it's listed in resolv.conf -- you probably want to remove it from resolv.conf so that it only gets used for the private.site domain. The nameservers in resolv.conf are essentially the defaults.

Best Answer

Related Solutions

DNSMasq – Setting Up DNSMasq for a Local Network

Using dnsmasq for accessing multiple nameservers assigned by DHCP

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