Creating Wildcard Records in DNS Forwarder/Resolver

A wildcard DNS record resolves <anything>.example.com to a single IP address, which can be useful in certain cases.

DNS Resolver (Unbound)

To create a wildcard entry the DNS Resolver (Unbound), use the following directives in the custom options box:

server:
local-zone: "example.com" redirect
local-data: "example.com 86400 IN A 192.168.1.54"

That makes any host under example.com resolve to 192.168.1.54. For example, www.example.com, thissitedoesnotexist.example.com, mystuff.example.com, and so on.

If there are existing Host Override or Domain Override entries for the same domain, these custom options may not function as expected. When overrides are present, the zone will already be defined but with a different zone type set. For domains associated with host overrides, the default behavior of the local zones can be altered with the System Domain Local Zone Type setting in the DNS Resolver Configuration.

DNS Forwarder (dnsmasq)

To create a wildcard entry in the DNS Forwarder, use the following directives in the advanced options:

address=/example.com/192.168.1.54

If a specific host override is set for example:

specific.example.com 192.168.1.100
knownhost.example.com 192.168.1.101

Then those would be returned when doing a query for those hosts, only when no specific host has been specified in the host overrides would the advanced wildcard entry be used.

To resolve the domain to an IP address:

example.com 192.168.1.45

Leave the host field blank in the host overrides. So if the query is now for example.com the forwarder will return 192.168.1.45. If a client requests knownhost.example.com then 192.168.1.101 would be returned instead.

If a blank hostname example.com host override entry has not been created, then a query for example.com would return the wildcard IP address set in the advanced option.

If a client queries for madeupname.example.com then since no specific host record for madeupname exists in the host overrides. The forwarder will return the wildcard entry of 192.168.1.54.