Filter with Jpcap

Question

I need to filter Telnet packets using Jpcap.. how can I do it? I've tried with:

captor.setFilter("telnet", true);

but it does not work...

Answer 1

you can filter telnet port (23):

captor.setFilter("port 23", true);

Answer 2

By calling your captor instance [captor.loopPacket(-1,handler)] with a handler like this :

public class TelnetReceiver implements PacketReceiver
{
    public void receivePacket(Packet p) 
    {
        if (p instanceof TCPPacket) { //Filter TCP only
            TCPPacket tcp = (TCPPacket) p;

            if(tcp.dst_port == 23 || tcp.src_port == 23)) {
                //Do something with tcp.data or other layer fields
            }
        }
    }
}