{根据机名获取IP，要添加使用单元：WinSock}
function ComputerIP(ComputerName:String):String;
var phe:pHostEnt;
  w:TWSAData;
  ip_address:longint;
  p:^longint;
  ipstr:string;
begin
  if WSAStartup(2,w)<>0 then exit;
  phe:=gethostbyname(pchar(ComputerName));
  if phe<>nil then
  begin
    p:=pointer(phe^.h_addr_list^);
    ip_address:=p^;
    ip_address:=ntohl(ip_address);
    ipstr:=IntToStr(ip_address shr 24)+'.'+IntToStr((ip_address shr 16) and $ff)
    +'.'+IntToStr((ip_address shr 8) and $ff)+'.'+IntToStr(ip_address and $ff);
    Result :=ipstr;
  end;
end;

function ComputerIP(ComputerName:String):String;
var phe:pHostEnt;
     w:TWSAData;
     ip_address:longint;
     p:^longint;
     ipstr:ansistring;
begin
    if WSAStartup(2,w)<>0 then exit;
    phe:=gethostbyname(pansichar(AnsiString(ComputerName)));
    if phe<>nil then
   begin
    p:=pointer(phe^.h_addr_list^);
    ip_address:=p^;
    ip_address:=ntohl(ip_address);
    ipstr:=IntToStr(ip_address shr 24)+'.'+IntToStr((ip_address shr 16) and $ff)
     +'.'+IntToStr((ip_address shr 8) and $ff)+'.'+IntToStr(ip_address and $ff);
    Result :=WideString(ipstr);
   end;
end;

function ComputerIP2(ComputerName:AnsiString):String;
var phe:pHostEnt;
     w:TWSAData;
     ip_address:longint;
     p:^longint;
     ipstr:ansistring;
begin
    if WSAStartup(2,w)<>0 then exit;
    phe:=gethostbyname(pansichar(ComputerName));
    if phe<>nil then
   begin
    p:=pointer(phe^.h_addr_list^);
    ip_address:=p^;
    ip_address:=ntohl(ip_address);
    ipstr:=IntToStr(ip_address shr 24)+'.'+IntToStr((ip_address shr 16) and $ff)
     +'.'+IntToStr((ip_address shr 8) and $ff)+'.'+IntToStr(ip_address and $ff);
    Result :=WideString(ipstr);
   end;
end;

{获取本机机名}
function GetLocalName():String;
   var
   CNameBuffer    :    PChar;
   CLen    :    ^DWord;
begin
   GetMem(CNameBuffer,255);
   New(CLen);
   CLen^:=    255;
   if GetComputerName(CNameBuffer,CLen^) then
     result:=CNameBuffer
   else
     result:='';
   FreeMem(CNameBuffer,255);
   Dispose(CLen);
end;

{获取本机IP，false可获内网IP, true获得外网IP。也要添加使用单元：WinSock}
Function GetLocalIp(InternetIP:boolean):String;
   type
     TaPInAddr = Array[0..10] of PInAddr;
     PaPInAddr = ^TaPInAddr;
   var
     phe: PHostEnt;
     pptr: PaPInAddr;
     Buffer: Array[0..63] of Char;
     I: Integer;
     GInitData: TWSAData;
     IP: String;
begin
     Screen.Cursor := crHourGlass;
     try
       WSAStartup($101, GInitData);
       IP:='0.0.0.0';
       GetHostName(Buffer, SizeOf(Buffer));
       phe := GetHostByName(buffer);
       if phe = nil then
       begin
         ShowMessage(IP);
         Result:=IP;
         Exit;
       end;
       pPtr := PaPInAddr(phe^.h_addr_list);
       if InternetIP then
         begin
           I := 0;
           while pPtr^[I] <> nil do
             begin
               IP := inet_ntoa(pptr^[I]^);
               Inc(I);
             end;
         end
       else
         IP := inet_ntoa(pptr^[0]^);
       WSACleanup;
       Result:=IP;//如果上网则为上网ip否则是网卡ip
     finally
       Screen.Cursor := crDefault;
     end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
// edit1.text = '127.0.0.1'，或者其它地址
ShowMessage( '计算机名:'+ UdpSocket1.LookupHostName(edit1.Text) + #13#10
+ '内网IP:'+ udpSocket1.LocalHostAddr);
end;

  ShowMessage(idIPWatch1.LocalIP);