UPnP Forward?

Discussion in 'DD-WRT Firmware' started by dd2k, Feb 3, 2006.

  1. dd2k

    dd2k Network Guru Member

    Could anybody explain to me what "UPnP Forward" in ddwrt does? I searched this in google and still dont have a clue.

    BTW, I think some example will also help.

    Best regards

  2. ericjwill

    ericjwill Network Guru Member

    UPnP is used to forward ports automatically for a program. For example: bittorrent needs a port open in your firewall to allow incoming connections, rather than configure port forwarding manually bittorrent merely talks to the router and gets its own port open automatically.

    Hope this helps.

    *edit* UPNP stands for Universal Plug and Play
  3. 4char

    4char Network Guru Member

    I guess, then, the question is that if it automatcally opens the port(s), why do we need this to manually set the port forwarding (in Applications & Gaming -> UPnP Forward)?
    Should Enable the UPnP in Administration -> Management is enough?
  4. vazel

    vazel Network Guru Member

    so with upnp manually setting in port forwarding settings is useless?
  5. dd2k

    dd2k Network Guru Member

    Exactly what I meant.
    Anyone notice "UPnP Forward" page looks a lot like "Port Forwarding"page. I guess maybe they have similar functionality.

    I know port trigging/forwarding make use of the linux iptables tool. The question is if "UPnP Forward" also uses iptables. I am not familiar with iptables, so could anyone point me out?
  6. ericjwill

    ericjwill Network Guru Member

    Not all programs use UPnP so some manual port forwarding is required. Most P2P apps support UPnP but if, for example, you are running IIS or Apache and want port 80 for the world to get to your page you will need to manually forward it. Most server software does NOT support UPnP software. Also, some games do not support it either. Look into your programs documentation to see what method it supports, manual or UPnP.
  7. dd2k

    dd2k Network Guru Member

    Well, I know what UPnP is and I also know what port forwarding is for. The question is what the heck (UPnP + port forward) could do.

    PS: I assume UPnP forward == UPnP + port forward and I know I could be very wrong.
  8. Kot_Behemot

    Kot_Behemot Network Guru Member

    My guess is that if you have a router connected to local network on the wan side(as it is my situation) it can forward your upnp request to the router one step further

    My comp->My_LAN->My_Router->LAN_Outside->Router2->Internet

    Its only a guess :).
  9. ericjwill

    ericjwill Network Guru Member

    I dont think the UPnP daemon runs on the WAN side of things, that'd be a good question for a developer. There probably is a way to have it run on both WAN and LAN, however. It probably requires telnet/sshing into the router or making a small startupscript.

    Port Forwarding + UPnP doesnt break anything if you are unsure of your program from my expierence.
  10. Kot_Behemot

    Kot_Behemot Network Guru Member

    @ericjwill -I believe that you missunderstood me- I meant that the UPNP packet is being recieved by ROUTER1, processed (ports being open), sent to another ROUTER2 (one step cloaser to internet), processed again. I thought it doesnt need any kind of deamon on wan side of router (only a thought).
    Of course it can be something totally different, as I believe you are more informed in this matter- I was just as curious as the author of this thread, when I saw this option in #23.
  11. ericjwill

    ericjwill Network Guru Member

    I am unsure if upnp requests can be made from router one to router two. Let me diagram what i think you are saying:

    CLIENT ~> UPNP REQUEST1 ~> ROUTER1 opens port X ~> forwards upnp request ~> ROUTER 2 opens port X forward from router one to internet

    As far as I know traditional UPnP requests stop at router one, as the computer behind Router one is on a different network than the network that is router 2 (which would require some sort of forwarding for either the UPnP packet to move past router one). As soon as a port is opened, the UPnP request is complete.

    It'd be some kind of awkward forwarding which may be beyond the spec of UPnP or require some fancy routing which beyond me. In reality the ROUTER1 would probably have to act as some form of transparent bridge to allow the upnp request to router 2. Or as I stated before some form of UPnP running on WAN of router one. Perhaps UPnP has some form of relay a la DHCP relay servers?

    Brainslayer, care to weigh in on this?
  12. cep6066

    cep6066 Network Guru Member

    on the same lines as UPnP Forwarding. I am using DD-WRT firmware and am having problems with my Roku Soundbridge and Rhapsody can anyone help me I am felling stupid :cry:
  13. danr

    danr Network Guru Member

    There were/are some issues with UPNP. Take a look at this thread, if you want to test an updated version:


    For all I know, you may have an issues with Soundbridge/Rhapsody, I haven't used them...
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