> The PPP traffic seems to refuse to be routed anywhere but the machine
> running pppd.

Do you have "options GATEWAY" in your kernel, or have you set the 
net.inet.ip.forwarding or net.inet6.ip6.forwarding sysctls?
("sysctl -a | grep forward" should tell you...)

> I also have some odd behavior with delays on the serial line
> where "ping" operations seem to acquire a latency equal to the
> ping interval, no matter what it is.  It looks to me like the
> line turnaround (data coming back the other direction) is triggering
> the response from the remote machine somehow.

I have seen this behavior somewhere before (on mac68k, not macppc)--it's
like the reciever interrupt is required to kick the transmitter.

-allen

-- 
   Allen Briggs                                     briggs@wasabisystems.com
   http://www.wasabisystems.com/      Quality NetBSD Sales, Support, Service