PPP / Routing table

[Denis Mysenko]

Hello everybody!

I got stuck here with PPP + Poptop :( I use Poptop 1.3.4 on FreeBSD
7.1-PRERELEASE for a VPN server.

As far as I understand, the problem is related either to userland ppp or to
FreeBSD itself and not to Poptop. So here it is:

There is a Poptop server running for several VPN clients, MPPE is enabled
for PPP. When somebody connects, tunnel interface is created and
corresponding entry in the routing table is made, like this one:
<client addr on tunnel dev> <my addr on tunnel dev>   UGH     0   0  tun0

Everything works fine, both with MPPE turned on and off. The problem starts
when second client connects to Poptop! New tunnel interface, let's say tun1,
is created correctly, with proper IP address. However, routing table is
updated with incorrect entry:
<new client addr> <my addr on tunnel dev> UGH 0 0 tun0

As we can see, FreeBSD added a routing entry going through the same tunnel
interface - of the previous client! So obviously new VPN connection doesn't
work. What is strange - is that it happens only when second client turns on
MPPE. With MPPE turned off - everything works fine.

I was playing a lot with different parameters and once I got everything
working, but not anymore :) Since I don't see any logical reason - I cannot
recover the proper config.

As far as I understand, so far, PPP creates a tunnel interface and then
FreeBSD, and not PPP, adds a routing table entry since a new network
interface was added - am I true? Local IP (my side of the PtP) for all
tunnel devices is the same - let's say 192.168.0.1. So as I see it, when
detecting corresponding interface FreeBSD chooses the first tunnel interface
because it has the same local IP. The question is - why does MPPE affect
this process? And it used to work half a day ago anyway.

Please - if anybody has any idea - could you help me!? :)

-- 
Sincerely,
-- 
Denis Mysenko, CCNA, MCP, MCSA
Technologies of the Smart City Ltd
Phone: +7 903 913-2651
ICQ: 555955