program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses

      PsAPI,

      WinSock,

      Windows,

      SysUtils;

    const

       ANY_SIZE = 1;

       iphlpapi = 'iphlpapi.dll';

       TCP_TABLE_OWNER_PID_ALL = 5;

       MIB_TCP_STATE:

       array[1..12] of string = ('CLOSED', 'LISTEN', 'SYN-SENT ','SYN-RECEIVED', 'ESTABLISHED', 'FIN-WAIT-1',

                                 'FIN-WAIT-2', 'CLOSE-WAIT', 'CLOSING','LAST-ACK', 'TIME-WAIT', 'delete TCB');

    type

       TCP_TABLE_CLASS = Integer;

      PMibTcpRowOwnerPid = ^TMibTcpRowOwnerPid;

      TMibTcpRowOwnerPid  = packed record

        dwState     : DWORD;

        dwLocalAddr : DWORD;

        dwLocalPort : DWORD;

        dwRemoteAddr: DWORD;

        dwRemotePort: DWORD;

        dwOwningPid : DWORD;

        end;

      PMIB_TCPTABLE_OWNER_PID  = ^MIB_TCPTABLE_OWNER_PID;

      MIB_TCPTABLE_OWNER_PID = packed record

       dwNumEntries: DWord;

       table: array [0..ANY_SIZE - 1] OF TMibTcpRowOwnerPid;

      end;

    var

       GetExtendedTcpTable:function  (pTcpTable: Pointer; dwSize: PDWORD; bOrder: BOOL; lAf: ULONG; TableClass: TCP_TABLE_CLASS; Reserved: ULONG): DWord; stdcall;

    function GetPathPID(PID: DWORD): string;

    var

      Handle: THandle;

    begin

      Result := '';

      Handle := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, False, PID);

      if Handle <> 0 then

        try

          SetLength(Result, MAX_PATH);

            if GetModuleFileNameEx(Handle, 0, PChar(Result), MAX_PATH) > 0 then

              SetLength(Result, StrLen(PChar(Result)))

            else

              Result := '';

        finally

          CloseHandle(Handle);

        end;

    end;

    procedure ShowCurrentTCPConnections;

    var

       Error        : DWORD;

       TableSize    : DWORD;

       i            : integer;

       IpAddress    : in_addr;

       RemoteIp     : string;

       LocalIp      : string;

       FExtendedTcpTable : PMIB_TCPTABLE_OWNER_PID;

    begin

      TableSize := 0;

      Error := GetExtendedTcpTable(nil, @TableSize, False, AF_INET, TCP_TABLE_OWNER_PID_ALL, 0);

      if Error <> ERROR_INSUFFICIENT_BUFFER then

         Exit;

      GetMem(FExtendedTcpTable, TableSize);

      try

       if GetExtendedTcpTable(FExtendedTcpTable, @TableSize, TRUE, AF_INET, TCP_TABLE_OWNER_PID_ALL, 0) = NO_ERROR then

          for i := 0 to FExtendedTcpTable.dwNumEntries - 1 do

          if {(FExtendedTcpTable.Table[i].dwOwningPid=Pid) and} (FExtendedTcpTable.Table[i].dwRemoteAddr<>0) then //here you can check the particular port

          begin

             IpAddress.s_addr := FExtendedTcpTable.Table[i].dwRemoteAddr;

             RemoteIp  := string(inet_ntoa(IpAddress));

             IpAddress.s_addr := FExtendedTcpTable.Table[i].dwLocalAddr;

             LocalIp          := string(inet_ntoa(IpAddress));

             Writeln(GetPathPID(FExtendedTcpTable.Table[i].dwOwningPid));

             Writeln(Format('%-16s %-6d %-16s %-6d %s',[LocalIp,FExtendedTcpTable.Table[i].dwLocalPort,RemoteIp,FExtendedTcpTable.Table[i].dwRemotePort,MIB_TCP_STATE[FExtendedTcpTable.Table[i].dwState]]));

          end;

      finally

         FreeMem(FExtendedTcpTable);

      end;

    end;

    var

       libHandle : THandle;

    begin

      try

        ReportMemoryLeaksOnShutdown:=DebugHook<>0;

        libHandle           := LoadLibrary(iphlpapi);

        GetExtendedTcpTable := GetProcAddress(libHandle, 'GetExtendedTcpTable');

        ShowCurrentTCPConnections;

      except

        on E: Exception do

          Writeln(E.ClassName, ': ', E.Message);

      end;

      readln;

    end.