IP Networking

How can change udp lenght?
Hello.
I have FreeBsd 4.7 and i want to change udp datagramm lenght.
Where it can be? What i must do? I can rebuild my core but it is not good for me.
Thanks!

The length of a udp datagram is decided by the program that constructs that datagram. Which udp datagrams do you want to affect? What size are they now and what size do you want?

And most importantly, why do you want to do this?

I have Ethernet network. My programs use UDP protocol.
My max packet size is 9Kb and i need more.

According to TCP/IP Illustrated, the max IP datagram is 65535 bytes, which means that you should be able to get 65507 bytes of user data in a UDP datagram.

But Rich Stevens found that kernel bugs sometimes impose other limits.

If you are using sockets, you can try a setsockopt() to increase the buffer size. Use both SO_RCVBUF and SO_SNDBUF. You can probably raise your limit somewhat this way. But you may max out at 32K.

Don't worry about ethernet. The IP layer will fragment the IP datagram as required. You will not exceed the max ethernet frame size no matter what you do.

Thank you for your help!!!!!!!