🚀 go-pugleaf

I'm trying to set up a PPP server for dialup on a linux box running
2.0.29 and pppd 2.2.0f. I have a ppp connection out to the internet 
on ppp0, and am running mgetty 1.1.0 on the incoming dialups. I have
configured /etc/ppp/options/ttyXX with proxyarp, but no asyncmap, dns_addr,
netmask or anything like that, and have setup the relevent IP addresses 
for each serial line.
When I dialin from another machine, a ppp connection IS established, with
the dynamic IP being allocated, however, that is as far as it gets.
I can't ping the remote machine from the server and the remote machine
simply can't access any network services. After a few minutes the line
drops and the logs on both machines say something like "terminating due
to no response from other side".

As I am able to initiate a ppp connection, I suspect that the problem lies
either in the pppd command or the routing table. I definitely do have IP
forwarding kernel support - I also have IP firewall support, but surely
this is not the problem, as all the machines on the lan are seeing the 
internet via ppp0 just fine.

Do I need to set an asyncmap - I'm very unsure as when to escape which
control chars and why, let alone what the <map> would be. What about the
netmask?
I have scoured every piece of documentation I can lay my hands on, and 
am still no closer to success. I'm sure it's one of those obscurely
simple probs that must have happened to someone before.

All clues wanted 
Mark