DNS lookup / reverse lookup
application looks up either a given hostname displaying it's IP address (es) ,which were delivered by the currently used DNS servers of the device, or reverse lookups up an IP address to a hostname. (reverse lookup is being supported with start of version 1.2).
It thus can be used if you need the IP address (es) of a given host's domain name. For example if you want to check your dynamic DNS IP of your home VPN gateway. Or if you want to check what name belongs to an given IP address. The usage of the DNS application is exactly as using the ping application. You can either enter the name to resolve directly or choose a destination from your favorites list.