Hostname lookup failure

At home I have a pfSense box which acts like a gateway to my network and I never need to worry about Internet access. Currently I'm away and trying to use FreeBSD but am unable to resolve hostnames - I get hostname lookup failure. This does not happen on Windows so it looks as though something is missing from my FreeBSD setup.

What do I need, on FreeBSD to resolve hostnames? I can PING the router and Internet sites by IP address so I know that networking is working.
The problem is that I have ifconfig_em0="DHCP" in /etc/rc.conf but I don't get hostname resolved, at least not under FreeBSD.
What hostname are you trying to resolve? Something on the internet? Or something from your internal network?