delphi2009 里面的控件 TIdSMTPRelay procedure TIdSMTPRelay.ResolveMXServers(AAddress: String);var IdDNSResolver1: TIdDNSResolver; DnsResource : TResultRecord; LMx: TMxRecord; LDomain:String; i: Integer; iPref: Word;begin { Get the list of MX Servers for a given domain into FMXServerList } if Pos('@',AAddress) > 0 then begin LDomain := Copy(AAddress, IndyPos('@',AAddress)+1, Length(AAddress)-Pos('@',AAddress)); end else begin raise EIdDirectSMTPCannotResolveMX.CreateFmt(RSDirSMTPInvalidEMailAddress, [AAddress]); end; IdDNSResolver1 := TIdDNSResolver.Create(Self); try FMXServerList.Clear; IdDNSResolver1.AllowRecursiveQueries:=True; if Assigned(IOHandler) and (IOHandler.ReadTimeOut <> 0) then begin //thirty seconds - maximum amount of time allowed for DNS query IdDNSResolver1.WaitingTime := IOHandler.ReadTimeout; //30000; end else begin IdDNSResolver1.WaitingTime := 30000; end; IdDNSResolver1.QueryType := [qtMX]; IdDNSResolver1.Host := DNSServer; IdDNSResolver1.Resolve(LDomain); if IdDNSResolver1.QueryResult.Count > 0 then begin iPref := High(Word); for i := 0 to IdDNSResolver1.QueryResult.Count - 1 do begin DnsResource := IdDNSResolver1.QueryResult; if (DnsResource is TMXRecord) then begin LMx := TMXRecord(DnsResource); // lower preference values at top of the list // could use AddObject and CustomSort, or TIdBubbleSortStringList // currently inserts lower values at top if LMx.Preference < iPref then begin iPref := LMx.Preference; FMXServerList.Insert(0, LMx.ExchangeServer); end else begin FMXServerList.Add(LMx.ExchangeServer); end; end; end; end; if FMXServerList.Count = 0 then begin raise EIdDirectSMTPCannotResolveMX.CreateFmt(RSDirSMTPNoMXRecordsForDomain, [LDomain]); end; finally FreeAndNil(IdDNSResolver1); end;end;
