DD-WRT: DNSMasq expand-hosts not working

This question is old, but it's one of the top google results for the issue, and I finally figured it out.

The problem is that's not what expand-hosts does. The documentation on it is very fuzzy, but what expand-hosts does is adds the domain to host entries in /etc/hosts, not to dns queries. So for example

/etc/hosts:

10.77.0.5 astatichostname

dnsmasq.conf:

expand-hosts
domain=example.com

Then dns queries for astatichostname.example.com will resolve to 10.77.0.5 (in addition to DNS queries for just astatichostname).

---

Solution:

So, the solution is to get dd-wrt to create the entries in /etc/hosts without the domain on them, and then tell dnsmasq to consider those host entries as part of the example.com domain when a fully qualified A record DNS query comes in.
To do this you have to:

1. Put the example.com domain in the Domain Name field on the Setup -> Basic Setup page under Optional Settings.
2. Blank the LAN Domain setting on the Services page under DHCP Server.
3. Add expand-hosts to Additional DNSMasq Options on the Services page under DNSMasq

Step #1 controls the domain= setting that gets put in the dnsmasq.conf file. Step #2 removes the domain from the entries that get put in /etc/hosts. Step #3 tacks the domain onto the entries in /etc/hosts when a fully qualified DNS query comes in.

I'm so glad dd-wrt made this nice and simple...

The following works for me on my DD-WRT:

expand-hosts
local=/lan/
domain=lan

I think it's because you're missing the local setting. I also have lan set as my "LAN Domain" in the GUI.