Hi,

Can anyone tell me a way to edit and send my own tcp/ip packets.

I've been playing around with a packet sniffer called Ethereal, but as far as I could see you couldn't send packets using it.

I would like to be able to see exactly how different protocols work and how firewalls and routers behave.

Thanks.

"wINJECT" is a program which allows you to craft your own packets... it's quite good, but for complicated transactions of data it's not so usefull. Get it anyhow and have a play.

What do you want to create packets for?

(Of course if you've got linux, you could get hold of the fantastic "hping" program... in fact the newest version ((not yet released)) is supposed to run under the windows environment - but then again, they might have stopped development, best check up on that one)

thanks I'll try it out.

I just want to see how tcp/ip works

I think if i understand how it works on the lowest level then other things will make more sense.

Such as routers running NAT,I've read about it providing a basic firewall but I don't quite understand how it prevents connections which initiate from outside.I think it has something to do with the packets having sequential numbers.

But anyway I've posted elsewhere on that so thanks anyhow.

You could also use Nemesis.
http://www.packetfactory.net/projects/nemesis/

The Windows version only runs from the command line. You'll also need to install WinPcap.