I'm successfully using LWIP_HOOK_DHCP_APPEND_OPTIONS() and
LWIP_HOOK_DHCP_PARSE_OPTION() to get a domain from DHCP via DHCP option 15.
Now I'm interested in possibly using that as a search domain. So if doing a look-up for "server", and DHCP option 15
specifies domain "example.com", then DNS could do a search for "server.example.com". But not if the original
look-up name includes a trailing dot. If the original name includes a trailing dot, e.g. "server.com.", then it
wouldn't try "server.com.example.com".
Note that the current functions in dns.c will fail a DNS look-up given a string
that ends with a trailing dot. Technically is this correct or incorrect? See
the following which discusses trailing dots in domain names:
http://www.dns-sd.org/trailingdotsindomainnames.html