scutil --dns, and part of it's output:
DNS configuration (for scoped queries) resolver #1 search domain : broadband nameserver : 192.168.1.1 if_index : 15 (en0) flags : Scoped, Request A records reach : 0x00020002 (Reachable,Directly Reachable Address)
What is the "broadband" search domain? I haven't found much about it.
dig broadband or
nslookup broadband doesn't find any results. The nameserver associated with
broadband is the router IP address