Ubiquiti EdgeMax DNS Lookups

This morning I solved one of those small niggling problems on my network.

The problem

DNS searches for hosts on my local network are not resolving. More specifically, fully qualified domain name (FQDN) lookups work and hostname lookups do not.

The investigation

Since FQDN lookups work, I know that DNS name resolution works.

For some reason Windows is not appending the local domain name suffix during DNS lookups.

In a Windows Domain environment this is not an issue as Windows will use the domain name as the domain suffix when doing DNS lookups.

In a Window Workgroup environment this is an issue.

The solution

The easy solution is to manually specify the domain suffix in the network adapter properties and this has some downsides.

  1. It is not universal, it must be manually applied to each Windows client.
  2. It only works with Windows clients.

The proper solution is to configure DHCP to send option 015 with the local domain name.

I have an Ubiquiti EdgeMax X router providing DHCP and DNS.


subnet-parameters "option option-015 <domainname.local>"

to the DHCP subnet solved the problem. Refreshing the DHCP lease on my local computer and unqualified hostname DNS lookups started working.