UPNP then non-UPNP

Discussion in 'Windows MSN Messenger' started by Peter, Aug 30, 2004.

  1. Peter

    Peter Guest


    My ISP has routers which are non-upnp thus MSN file
    transfer is slow when sending to other users from my ISP.

    But when sending files/webcam/voice with users from other
    ISP things are fine. Thus meaning that it is sufficent
    with only one end to have UPNP (please correct me if i'm

    My question now is, if I put another router (which DOES
    support UPNP) between my computer and the non-upnp, will
    file transfer work better then ?

    Or does UPNP require that the last router must support

    Finally, in XP Control Panel -> Add Remove Programs ->
    Windows Components -> Networking Services. There is an
    item which is called "internet gateway device discovery
    and control client". Is it nescessary to have this
    installed in order for msn file transfer to work?

    There are also two services, one is called SSDP Discovery
    Service with description: "enable discovery of UPNP
    devices on your home network". state: RUNNING

    and Universal Plug and Play device host with desc:
    Provides support to host UPNP devices. state: STOPPED

    Are any of these services required for MSN Messenger?
    Is my system setup correct or should both be running?

    Please advice
    Peter, Aug 30, 2004
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  2. Greetings Peter,

    Believe it or not (and even contrary to some things I've said in the past, merely to avoid
    complicated matters), Messenger can actually get past some non-UPnP NAT based solutions and
    make use of UPnP (or a direct connection) of your contact in order to establish a direct
    connection for file transfer, etc.

    UPnP as a technology doesn't "require" anything except for that the device in question have
    UPnP support in order to make use of UPnP. If your ISP is NATing your connection or if the
    modem provided by your ISP has a non-UPnP NAT (that you can't turn off), adding an additional
    router on top with UPnP will not magically make it work in more scenarios.

    Messenger can actually make use of UPnP without these services but it is recommended that you
    leave them on (simply because some routers require it in order for UPnP to work properly,
    whereas others do not). In your particular scenario however, where there is a non-UPnP NAT,
    you don't need them (it won't change anything).

    Just to make clear, UPnP's purpose (Messenger-wise; UPnP is actually a very wide scoped
    technology) is to simply discover your external IP and open/forward/close ports, all the
    other "magic" is solely within Messenger itself.

    All posts unless otherwise specified are (c) 2004 Jonathan Kay.
    You *must* contact me for redistribution rights.
    Jonathan Kay [MVP], Aug 30, 2004
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  3. Peter

    N. Miller Guest

    Jonathan said a lot. I think simpler, based on watching the local action, is

    UPnP is necessary to control the router being traversed by the messenger
    packets. The last NAT router, the one with the public WAN IP address, has to
    be UPnP capable, or all bets are off. (If there are concatenated NAT
    routers, all should be UPnP enabled. I have actually done this.) If your ISP
    provides NAT service, and that NAT router is not UPnP enabled, UPnP won't be
    able to open ports on that router.

    If that is your situation, then adding a NAT router of your own, and
    enabling UPnP on your computer will not help.
    It is probably somewhat correct. I believe (I have not actually examined any
    packets since installing UPnP able equipment) that the remote UPnP NAT will
    properly identify the destination public IP address, and route the packets
    through that NAT to you. Your own response will already know which
    destination IP address and ports to use, so things work. But, if you
    initiate, instead of responding, it won't work. You can't get out of your
    N. Miller, Sep 1, 2004
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