Re: Networking problem....

[Adam Tauno Williams <adam@xxxxxxxxxxxxxxxx>]

>This is a problem being encountered by a colleague, as explained to
>me...
>He wants to run VPN through an IDSN (Pipeline) router, which does NAT.

As in Ascend Pipeline?

>The software on both ends has been configured, and it worked when he
>dials up an ISP (w/o using ISDN).... 

He is the "client-side" of the VPN?  (i.e. he initiates the connection to a
"server" that is awaiting his connection).

What kind of VPN?  IPSec, PPTP, etc...

>the question boils down to... why doesn't it work through the router? 

Most likely the router only does (or is configured to do) TCP/IP and UDP/IP. 
PPTP at least uses GRE/IP for session setup and management which means it won't
work via most routers/firewalls.  

>(and thus) How can the router configuration be changed to accomodate 
>all of this?

It may be a config issue, or not.  Some routers can't MASQ/NAT GRE and GRE does
not have the concept of "ports" like TCP or UDP does,  it has "connection
numbers" which are negotiated (sort of).  I don't know if Ascend can process
GRE, but Linux can ;}.

Systems and Network Administrator
Morrison Industries
1825 Monroe Ave NW.
Grand Rapids, MI. 49505