u_long inet_addr ( char * addr );

addr  --  Internet address in dotted decimal notation
returns --  Internet address in network byte order

char * inet_ntoa ( struct in_addr in );

in  --  Internet address in network byte order
returns -- Internet address in dotted decimal notation

struct hostent * gethostbyaddr ( char * addr , int len , int domain );

addr  --  pointer to address in network byte order. typically held in an in_addr structure
len  --  length of structure in bytes
domain  --  domain type, typically AF_INET
returns -- hostent structure with requested information

struct hostent * gethostbyname ( char * hostname );

hostname  --  hostname such as www.hethmon.com
returns -- hostent structure with requested information

int getpeername ( int socket , struct sockaddr * addr , int len );

socket  --  socket number currently connected to client. typically from an accept call.
addr  --  pointer to a struct sockaddr_in structure which holds the return information about the client. must be cast in call
len  --  length of structure in bytes
returns --  zero on success