RV082 port forward issue; Can't forward from port 'x' to port 'y'

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by 0x0A0B0C0D, May 18, 2008.

  1. 0x0A0B0C0D

    0x0A0B0C0D Addicted to LI Member

    I have a device on my LAN that is managed through port 443. I want to manage that device from the WAN side, however. My original plan was to choose some arbitrary large port number on the WAN side and forward it to the internal address 192.168.168.x:443. That way I can use a web browser and point it to [externalIP]:55443 and then be transferred to 192.168.168.x:443.

    So I peruse through the RV082 and discover, to my consternation, that it appears that the device cannot map an external port to a different internal port. :confused:

    I may be able to change the listening management port on the internal device to the preferred port of 55443... but maybe not. I'll look into it next week.

    Until then, am I missing something obvious? Any suggestions.
  2. vpnuser

    vpnuser LI Guru Member

    Look at Setup>UPnP for such configuration.
  3. 0x0A0B0C0D

    0x0A0B0C0D Addicted to LI Member

    Thank you!

    Thanks for the tip. It worked perfectly!
  4. aver5

    aver5 LI Guru Member

    can you show us in details how you have configured UPnp and forwarding for sample below ?
  5. 0x0A0B0C0D

    0x0A0B0C0D Addicted to LI Member

    Instructions for UPnP port forwarding

    First I'd like to say that I'm rather puzzled as to why this feature is under UPnP. I admit that I'm not terribly familiar with UPnP, but it seems that the ability to map an external port to an internal port of a different number predates the existence of UPnP nor does it rely on anything unique to UPnP. Corrections to my understanding are welcome.

    Here's detailed instructions on how to map an external port to a different internal port.

    1) In the RV082 under the "Setup" main category, select the UPnP subcategory.

    NOTE: The "UPnP Function: [] Yes [] No" option does NOT need to be set to 'yes' for this to work.

    2) Click "Service Management". You will see the screen that is in the attached JPG file.

    At this point, you can create your own brand new port mapping rule or start from a list of common protocols that are listed to the right.

    3a) If you select a predefined service, just change the internal and external ports as needed. NOTE: Make sure to click both "Add new" and "Save Setting" before leaving this screen.

    3b) If you need to create a brand new port mapping rule, give it a friendly name, select TCP or UDP, and then define the external and internal port numbers. NOTE: Make sure to click both "Add to list" and "Save Setting" before leaving this screen.

    4) Back at the main UPnP screen, select the newly created service from the service drop-down list, type in the internal IP address that you want to have associated with the port mapping, check the "Enable" box, and click "add to list".

    5) Make sure to click "Save Settings" at the bottom of the page. I've been bitten a few times in other screens for not clicking that. :hmm:

    That should do it.

    Bonus info: This scenario caused me to look more closely at just what exactly UPnP is. After some sleuthing, I discovered a good UPnP tool that allows you to scan for UPnP devices, poke them for information, and even feed new info to them. Take a look at it: http://noeld.com/programs.asp?cat=dstools#UPnPTest Fearful at the amount of info that can be offered through UPnP, I used that tool to do an audit on a client's network. Fortunately UPnP was not present on any device on the LAN.

    Also, Noel has a ton of other cool tools, so check those out as well. No, I'm not a paid sponsor. :smile:

    Attached Files:

  6. d__l

    d__l Network Guru Member

    I can't say why Linksys puts that port remapping feature under UPnP, but that is the way they do it on many (most?) of their routers.
  7. aver5

    aver5 LI Guru Member

    Many thank's for your explanation
  8. Toxic

    Toxic Administrator Staff Member

    Question: On RV0xx routers, why Port Forwarding is configured on the Setup>UPnP page?

    Answer: UPnP is a protocol that can be used by PC's in the LAN of RV0xx to set up port forwarding rules whose external port number is different from internal port number.
    When UPnP is enabled on RV0xx, port forwarding rules can be set up dynamically on routers via UPnP. If the administrator does not want to enable UPnP, e.g. due to security concern, the same type of forwarding rules can be configured manually. On RV0xx, the configuration of this type of forwarding rules happens to be located at the Setup>UPnP page. Note that the manually configured forwarding rules can work regardless whether UPnP is enabled on the router. In addition, the port forwarding rules on Setup>UPnP page should not conflict with the simple port forwarding rules defined on the Setup>Forwarding page, as it may result in unpredictable results
  9. Toxic

    Toxic Administrator Staff Member

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