It's my guess that a lot of you, experiencing this problem, are owners of dual processor G4s, right?
OS X's ppp-implementation has a bug that is triggered on these machines. In version 10.0.0 and -.1 this could even result in kernel panics. The kernel panics was fixed in version 10.0.2, but the ppp disconnect problem still persists. And Apple is rather reluctant to comment, after what I've read on the MacNN forums.
There is a hack that fixes the problem for some users (by Louis Gerbarg, a carbon developer), but not for all. For some, switching off echo-checks works, but many - as I do - still gets both disconnects and echo-checks.
Another way to fix this is to disable one processor, but does anyone really want to? Not me...
What really makes this rotten is the implied catch-22: To fix I need to download upgrade (if Apple ever gets its rear in gear - Norwegian expression...). But the bug... see?
The OS and the machine that was meant for each other - just aren't.
