>pppd does not properly understand LCP echo-response packets.

That's odd, since I have been using these options for months with
perfect results.

>This is easily demonstrable if you turn put these lines in /etc/ppp/options:
>
>lcp-echo-interval 5
>lcp-echo-failure 3

Of course, this is definitely not a recommended set of values since
you only get 15 seconds, even on a very busy line, to get the echo
packets through.

I use...

lcp-echo-interval 30            # check for active peer every 30 seconds
lcp-echo-failure 3              # terminate after 3 dropped echos

... in my own system.

I have never had problems with getting the echo packets through,
except for one time when I couldn't get the connection to come up
completely for a different reason.

>In about 15 seconds after establishing the connection, pppd will
>decide it is nonresponsive and kill it.  Turning on the debugging
>traces shows that the bottom i/o layer of pppd reads the echo response
>and it looks fine, but the LCP layer erroneously decides the packet is
>bogus and ignores it.

Is your pppd connection *fully* established?

-----------------------------------------------------------------------------
   Michael L. VanLoon     michaelv@HeadCandy.com     michaelv@iastate.edu
  Free your mind and your machine -- NetBSD free un*x for PC/Mac/Amiga/etc.
     Working NetBSD ports: 386+PC, Mac, Amiga, HP300, Sun3, Sun4c, PC532
               In progress: DEC pmax (MIPS R2k/3k), VAX, Sun4m
-----------------------------------------------------------------------------