I believe I've found a bug in the 6.0 implementation of PPP.
Connecting to the Ricochet network (a standard PPP server)
I couldn't send large packets. Pings worked fine, small
web pages worked fine, but large packets couldn't get
through. (Turning on kernel debugging showed that the
large frames would arrive, but wouldn't "get through".)
After struggling for 48 hours on the problem, I found that
I could work around it by specifying "novj" (turn off
Van Jacobson compression.)
A quick search of the newsgroups shows that this problem
affects many people.
This is in the kernel, not the ppp daemon. The ppp daemon merely sets up
the connection; the kernel is in charge of the rest.
Ricochet does indeed have problems with VJ compression having reviewed some
packet and byte traces. I've moved this bug to Michael because the only answer
I see is to put Ricochet into RP3 and make RP3 know about VJ disable on some
Adding every possible option to rp3 will turn it into a user interface
nightmare. I'd rather just explain how to work around ricochet's bugs
until they get them fixed. linuxconf does have a way to set PPPOPTIONS
so folks can use that to set PPPOPTIONS=novj to work around the problem
in the meantime. AT&T chose the same kind of thing when they found a
bug in their implementation that kept CCP negotiation going -- they
preferred to tell people to set PPPOPTIONS=noccp to adding a bug-compat
features to rp3 or some other tool.