PPTP with MPPE & RIP not working between Cisco4500 & WinXP native VPN

Discussion in 'Cisco' started by Pedro Ribeiro, Dec 14, 2003.

  1. I'm having a wierd problem with a VPN dialup that I'm using for remote
    administering the network.
    The VPN Concentrator is an old C4500M using protocol PPTP with MPPE &
    MPPC, in the client side I'm using the VPN client built in WindowsXP.

    The VPN is working without problems since i'v started to use it but
    now I wanted to get rid of the script I use to start the VPN that
    cleans the routing table (inserts/removes some routes).

    I'v configured the C4500 to send the correct routes using RIPv2
    (broadcast destination) over the "virtual-template" interface and the
    problem is that the "RIP Listner" included in WinXP doesn't receive
    any announces.

    Curious is the fact that I can get the RIP announces in the client
    using a "sniffer" application, but neither "RIP Listner" or "netcat"
    (listening in port 520/UDP) recieves any announce.
    More curious is the fact that RIP announces captured by the "sniffer"
    aren't ciphered, they travel encapsulated in GRE/PPP (PPTP data flow)
    but in cleartext while all the other traffic arrives ciphered.

    Establishing the VPN without MPPE/MPPC active, the RIP announces reach
    the "RIP Listener" that populates the routing table without problems.

    Is there any way to get RIP working at the client with MPPE active in
    the tunnel ?

    Can I force the RIP packets to travel encrypted in the Cisco side ?
    Can I "relax" the MS VPN in the client side to accept the unencrypted
    packets and pass them to UDP (some registry key) ?

    Pedro Ribeiro, Dec 14, 2003
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