RE: [Poptop-server] server>fw---fw<client problems

[Craig <jo...@us...>]

>> situation:
>> poptop server behind a firewall at work, various clients 
>> behind a linux 
>> MASQ box trying to connect.
>> 
>> Everything's worked as recently as this morning; I can't 
>> figure out what 
>> the problem is now.
> 
> Things necessary for poptop to work:
> 
> 1 - TCP 1723 and Protocol 47 must be allowed to pass-through.
> 2 - Poptop has to have ppp & kernel patched with MPPE support
> 3 - Poptop needs the proper configuration
> 4 - Client needs to be properly setup
> 
> Can you say for sure that all these steps are working?  If so, what 
> have you
> done to test them?

The server's running poptop-1.1.3-20030409 and pppd-2.4.1, no kernel or 
pppd patches, port 1723 is forwarded from the border.

The client is a Winxp laptop using the built-in MS VPN client, behind a 
linux nat firewall (kernel 2.4.18, modules iptable_filter ipt_MASQUERADE 
iptable_nat ip_conntrack ip_tables) with a pppoe dsl connection (ppp0) 
to my ISP.

I got the vpn working again with the following iptables rule on the 
client side firewall:
iptables -t nat -A PREROUTING -i ppp0 -p 47 -j DNAT --to vaio

Still trying to figure out what necessitated the rule, as I said it has 
worked fine to date with no more than the simple
iptables -t nat -A POSTROUTING -o ppp0 -s local-net/24 -j MASQUERADE

Craig