IP nach Hostname

[Delphi.Narium]

Schau bitte mal, ob Du aus diesem Quelltextfragment schlau wirst (hab' ich in 'nem alten Delphi-7-Programm gefunden):

Delphi-Quellcode:

// DNS = TIdDNSResolver
    s             := 'www.delphipraxis.net'; // oder eine IP
    DNS.Host      := Reg.NameServer; // Dein DNS-Server
    DNS.ClearInternalQuery;
    DNS.QueryType := [qtA]; // Liefert einen A- und einen Name-Record - hier auch mal die anderen möglichen Varianten probieren z. B. qtName
    Reg.WriteAppInfoLog(Format('DNS-Abfrage: Host = %s',[s]));
    Try
      DNS.Resolve(s);
      Reg.WriteAppInfoLog('DomainName: %s',[DNS.QueryResult.DomainName]);
      if DNS.QueryResult.Count > 0 then begin
      for i := 0 to DNS.QueryResult.Count - 1 do begin
        case DNS.QueryResult.Items[I].RecType of
          qtA: begin
                 if Trim(TARecord(DNS.QueryResult.Items[I]).IPAddress) = '' then begin
                   Reg.WriteAppInfoLog('IP: %s', [GetIPFromRData(DNS.QueryResult.Items[I].RData)]);
                 end else begin
                   Reg.WriteAppInfoLog('IP: %s',[TARecord(DNS.QueryResult.Items[I]).IPAddress]);
                 end;
              end;
          qtNS: Reg.WriteAppLog('    ' + TNSRecord(DNS.QueryResult.Items[I]).HostName);
          qtMD: Reg.WriteAppLog('    ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
          qtMF: Reg.WriteAppLog('    ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
          qtName: Reg.WriteAppLog('    ' + TNAMERecord(DNS.QueryResult.Items[I]).HostName);
          qtSOA: begin
                   Reg.WriteAppLog('    Primary:           ' + TSOARecord(DNS.QueryResult.Items[I]).Primary);
                   Reg.WriteAppLog('    ResponsiblePerson: ' + TSOARecord(DNS.QueryResult.Items[I]).ResponsiblePerson);
                   Reg.WriteAppLog('    Serial:            ' + IntToStr(TSOARecord(DNS.QueryResult.Items[I]).Serial));
                   Reg.WriteAppLog('    Refresh:           ' + IntToStr(TSOARecord(DNS.QueryResult.Items[I]).Refresh));
                   Reg.WriteAppLog('    Retry:             ' + IntToStr(TSOARecord(DNS.QueryResult.Items[I]).Retry));
                   Reg.WriteAppLog('    Expire:            ' + IntToStr(TSOARecord(DNS.QueryResult.Items[I]).Expire));
                   Reg.WriteAppLog('    MinimumTTL:        ' + IntToStr(TSOARecord(DNS.QueryResult.Items[I]).MinimumTTL));
                 end;
          qtMB: Reg.WriteAppLog('    ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
          qtMG: Reg.WriteAppLog('    ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
          qtMR: Reg.WriteAppLog('    ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
          qtWKS: begin
                   Reg.WriteAppLog('    ' + TWKSRecord(DNS.QueryResult.Items[I]).IPAddress);
                   Reg.WriteAppLog('    ' + IntToStr(TWKSRecord(DNS.QueryResult.Items[I]).Protocol));
                 end;
          qtPTR: Reg.WriteAppLog('    ' + TPTRRecord(DNS.QueryResult.Items[I]).HostName);
          qtHINFO: begin
                     Reg.WriteAppLog('    ' + THINFORecord(DNS.QueryResult.Items[I]).CPU);
                     Reg.WriteAppLog('    ' + THINFORecord(DNS.QueryResult.Items[I]).OS);
                   end;
          qtMINFO: begin
                     Reg.WriteAppLog('    ' + TMINFORecord(DNS.QueryResult.Items[I]).ResponsiblePersonMailbox);
                     Reg.WriteAppLog('    ' + TMINFORecord(DNS.QueryResult.Items[I]).ErrorMailbox);
                   end;
          qtMX: Reg.WriteAppLog('    ' + TMXRecord(DNS.QueryResult.Items[I]).ExchangeServer+',' + IntToStr(TMXRecord(DNS.QueryResult.Items[I]).Preference));
          qtTXT: Reg.WriteAppLog(TTextRecord(DNS.QueryResult.Items[I]).Text.Text);
          else
            Reg.WriteAppLog('?:');
            Reg.WriteAppLog('   ' + TResultRecord(DNS.QueryResult.Items[I]).Name);
            Reg.WriteAppLog('   ' + TResultRecord(DNS.QueryResult.Items[I]).RData);
          end;
        end;
      end else begin
        Reg.WriteAppErrorLog('Kein Ergebnis erhalten.');
      end;
      DNS.Disconnect;
    except
      on e : Exception do begin
        Reg.WriteAppInfoLog('DNS-Abfrage: ' + e.Message);
        try
          DNS.Disconnect;
        except
        end;
      end;
    end;

...

function GetIPFromRData(RData : TIDBytes) : String;
var
  s : String;
  i : Integer;
begin
  s := BytesToString(RData);
  if Length(s) = 4 then begin
    Result := '';
    for i := 1 to Length(s) do Result := Result + IntToStr(Ord(s[i])) + '.';
    Result := Copy(Result,1,Length(Result) - 1);
  end else begin
    Result := s;
  end;
end;