We are developing a application to recieve UDP broadcast from a third party application. Wireshark shows packets of 512 bytes. Each packet have header information. Below is 8 bytes as wireshark shows
01 00 5E 01 02 05 00 11
I have created a small consol based application C# to listen on that specific port. Below is what i am geeting as first 8 bytes.
04 20 00 01 00 00 04 59
Can someone explain it?
Wireshark typically shows the entire packet which is described here. The first 4 bytes you show might be the port numbers (256 and 24065 ... not sure if those make sense or not in your case). If your console application is doing something equivalent to a recvfrom, it will include the payload portion but not the header.
As Mark Wilkins says, Wireshark is showing the entire packet, up to and including the link layer headers.
To see the data you're interested in, follow these steps:
In the middle frame of the window, there should be a bunch of lines - the first one starts with something like "Frame". The second-last one should be "User Datagram Protocol", and the last one "Data". Click on the last one, and it should then highlight the actual UDP payload bytes in the bottom frame of the window.