UDP limitations

Projects Programming
1

Hello, I am trying to send two different UDP packets from my Arduino to a PC. That is, I open an UDP port on my Arduino and try to send two strings ("ack1" and "ack2") to two different UDP ports on a PC. I tried in several way, but I just can't do it! On the PC side I read on both ports the same message: "ack2". Message "ack1" is never seen.
I would like to ask if someone knows this issue and if is it possible to bypass it in some way. :~

Thanks a lot

Test code follows:

byte mac[] = {  0x90,0xA2,0xDA,0x00,0x4E,0x22 };
IPAddress ip(10,0,0,2);
IPAddress remoteip(10,0,0,1);

unsigned int localPort = 8888;      // local port to listen on
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
char  ReplyBuffer[] = "ack1";
char  ReplyBuffer2[] = "ack2";
EthernetUDP Udp;
void setup(){
   Ethernet.begin(mac,ip);
   Udp.begin(localPort);  
}

void loop(){
  
    Udp.beginPacket(remoteip,9000 );
    Udp.write(ReplyBuffer);
    Udp.endPacket();
    delay(1000);

    Udp.beginPacket(remoteip,9001 );
    Udp.write(ReplyBuffer2);
    Udp.endPacket();
    delay(1000);
}
2

You should check return values. All three calls to your Udp object return result codes. If there is an error you should react accordingly. Your second call to beginPacket() might fail and you won't notice resulting in wrong behaviour. From what your results are I guess the second call to Udp.write() fails. This at least would explain the described behaviour.