Port forwarding - Still need to open port?

Discussion in 'DD-WRT Firmware' started by eobiont, Mar 11, 2006.

  1. eobiont

    eobiont Network Guru Member

    I have forwarded a single port to a machine on my lan, but I can't get the application that uses this port to connect over that port - say port 12345

    I know the application is listening on that port because if I use the internal address, it works fine. It is not able to use the external address.

    so my internal address is
    the external address is say,

    If I am on the wireless lan connected to the router, I can connect to using the port 12345, however if I try to connect to it doesn't work. I thought this might be because the router sees my address as being on the wireless lan, and so the traffic doesn't go through the firewall, but this isn't the case.

    I tried the same thing, connecting first to a VPN at my work so that I would have a foreign IP address. Still wouldn't work.

    It seems like in the past I have had to open up the port on the router in addition to forwarding it, but I don't see the spot in dd-wrt to open ports. I would like to restrict this port so it can only be used by a range of external ip addresses rather than open to the world, but I don't even see the option to open the port to the world - just where to set the forward.
  2. eobiont

    eobiont Network Guru Member

    I listed my open ports and there is this line

    ACCEPT tcp -- anywhere htpc tcp dpt:12345

    htpc is the dhcp client name of the machine I forwarded this port to. Should this really be listed as that name and not the IP address? I listed the IP address in the port forwarding screen - not the dhcp address. dd-wrt switched it to "htpc".

    Also, it looks like here is where I want to get rid of "anywhere" and put in my range of addresses. Is there a gui for managing this ports list or do I have to do it via telnet??

    At the risk of being flamed into next week, this was really easy to set up on my dlink router.
  3. bigjohns

    bigjohns Network Guru Member

    not exactly sure what you're wanting - but is Loopback enabled?
  4. eobiont

    eobiont Network Guru Member

    I've made some progress here.

    I was just coming back to leave an update and saw your response.

    I figured out how to forward a port and could tell from https://www.grc.com/x/portprobe=12345 that I had got the port open correctly.

    The next step was to close the port off to the whole internet except for a few selected outside IP addresses.

    I downloaded fwbuilder for my Macintosh and followed the great tutorial at that web site. I used the tool to open port 12345 and lock it down so it was only open to a few IP addresses.

    The problem now is that I need would like to do this to a couple additional ports. The problem is that when I uploaded the firewall to the linksys, I noticed that it said that there were only 2 bytes left. That's no good.

    I need a little nudge in the right direction on what to do next. I'm guessing this means that I'm nearly out of nvram. What do I do about that?
  5. eobiont

    eobiont Network Guru Member

    Port forwading working now - but uPNP is broken


    I ended up installing ddwrt-mini and activating jffs. My firewall loads correctly at each boot.

    My problem now, is that uPNP no longer works.

    What do I have to do in fwbuilder to enable uPNP (if that is where the problem lies)
  6. bigjohns

    bigjohns Network Guru Member

    upnp should be enabled in the web/gui if it exists in -mini-
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