Frequently Asked Questions

TCP/IP: Retrieving Client IP and Host Name

Question:

At client, how can I get the IP address or host name of

itself.

Answer:

The following example requires using the Winsock API 

encapsulated in WinSock.pas.



uses

  WinSock;



procedure GetHostInfo(var Name, Address: string);

var

  WSAData: TWSAData;

  HostEnt: PHostEnt;

begin

  { no error checking...}

  WSAStartup(2, WSAData);

  SetLength(Name, 255);

  Gethostname(PChar(Name), 255);

  SetLength(Name, StrLen(PChar(Name)));

  HostEnt := gethostbyname(PChar(Name));

  with HostEnt^  do

    Address := Format('%d.%d.%d.%d',[

      Byte(h_addr^[0]), 

      Byte(h_addr^[1]),

      Byte(h_addr^[2]), 

      Byte(h_addr^[3])]);

  WSACleanup;

end;