IP Fragments - Worth doing, testing strategies?

I have been working on my TCP/IP stack for DOS, adding IP fragmentation support. There are not too many more features that I want to add to make it 'complete' before I open source the code and IP fragment support was a big one. I am having a terrible time testing it though. It seems that IP fragments out in the wild are pretty rare. I tried connecting to a slew of remote FTP sites hoping to find one that was behind a really bad network, and thus would have fragments coming from it. No joy. It seems that there are a lot of tricks out there to prevent fragments the code is to send myself oversized UDP packets. If it works for UDP then it should work for TCP too, but I'd really like to test the TCP path explicitly. Combine the tricks with modern broadband and getting fragments is really difficult. Even on the home network I am having a hard time getting fragments. I put a Linux box between the DOS PC and a Windows machine, and set one of the Ethernet MTUs to 576. Well, that didn't force fragments because the Windows box is too clever. I could start turning everything off in the registry, but I really don't want to get that involved. Off the top of my head I think I am going to have to get another Linux box and dumb that down, if it is possible. Dumbing Linux down to turn off the features and then restoring it to a good state is probably safer/easier than doing it with Windows. Does anybody have a good technique for setting up a simple network that will result in IP fragments of TCP? On a related note, is this even worth it? I don't know of anything that needs to send fragments except for NFS over UDP. There might be other applications that send big packets over UDP but those would be the only class of applications that absolutely require fragment support. With TCP it is nice, but a user should be able to get around any problem by setting the local MTU to 576. Mike