From the NannyMUD documentation

LAST CHANGE

2000-12-11

FUNCTION

NAME
        query_ip_name - give the hostname from which a player is connected


SYNTAX
	string query_ip_name(void|object player)

DESCRIPTION
	Gives the host name of an interactive player, ie from which site
	the player is connecting to the game.
	
	The string returned is on the form: "milou.cd.chalmers.se"


NOTE
	This function demands an external process to be active on the
	machine running the gamedriver. If that process is not active
	query_ip_name will return the same as query_ip_number, always.


SEE ALSO
        query_ip_number in efun/player_related/query_ip_number