I REALLY need some help opening a tcp port... please take a gander >>

Hi guys,
I've been working on getting a tcp port open now for 3 days. I have used TH site for years for my system builds and general info so I've come here for help alas. I'm trying to open a tcp port and having absolutely zero luck. I've tried 3 torrent clients so far so I'm relatively convinced it's not the client and it's my pc. Currently I'm testing w/ edonkey because it has a nice "check ports" feature.

I've turned my win fw "off" for all testing as of late to try and rule that out, although I'm not certain turning this on and off does anything at all, the process is instant and I see no changes at all. Matter of fact when I turn the fw off, I still see the sevice as "started" when looking under windows "services". When I was testing with win fw on I did have exceptions installed for TCP and UDP ports.

I have also taken my router out of the loop for now until I get this working, then I'll set it back up and forward the ports.

I have a Motorola SB5100 cable modem, my ISP is telling me they are not blocking any ports and that my modem isn't either (although I suspect this modem may actually be the problem). Upon logging into my modem I found I cannot view or change anything, they must dumb these things down before they hand em out to general customers. I've had this modem for years.

My ipconfig shows the following:
ip address
gateway and dns

Why am I not seeing my public ip address here unless this modem is acting as a router?
I dont' have a static IP set up on my pc, everything is set to auto.
I've gone through all the faq's and suggestions at portforward.com (most of which don't apply as I have no router now).

Can one of you guru's PLEASE help me out here, I'm at my wits end. I'm thinking either my windows firewall settings are not taking, how can they have no affect at all on my security? Using Shield Up https://www.grc.com is telling me I'm in complete "stealth" mode even with my windows fw completely off?

Edit: Forgot to mention, I'm running free AVG which I'm sure does not have any firewall capability. I get the same result w/ AVG closed and processes killed.

I'm about to set myself on fire
Thanks guys
22 answers Last reply
More about opening port gander
  1. Your modem is not online. When a cable modem boots up, it assigns a private IP address first and then the public one when it's up.

  2. Thanks grumpy. What do you mean it's "not online"?
    Anyone have any suggestions, still haven't gotten this working.....
  3. Can you connect to the internet normally? If so then your modem is online.

    A good way to see your external IP address is by going to: http://www.whatismyip.com/

    I am leaning towards your modem being the issue. The stealth mode if i remember correctly means your modem is NATing so the outside world can't see you.
  4. Hey man, that is EXACTLY what I think is going on. I can't see ****! Can't connect to any tcp ports whatsoever, I thought it may be my NIC driver using some sort of built in firewall but I downloaded a new driver and same result. Like I said my windows firewall condition has no effect on anything, wtf, I'm getting very frustrated working on this for 4 days now.

    Can you point me in the right direction please? What can I do to config my modem, when I log into it I can't change anything?

    Yeah, I can surf and such okay....
    Oh and yea, I can see my public IP once online, but shouldn't my ipconfig show me a public IP and not a private?
    Thank you sir.
  5. Also, Lvdax... if my modem was NATing as you suggest, would that also be blocking all my tcp ports... ie trying to use a torrent program or the like?
  6. A Motorola SB5100 cable modem does not use NAT. Is the Online light on solid or blinking? If it's blinking, you need to contact your cable company.

  7. online light is solid.. I'm getting around 6M on speedtests for my network is performing "okay". But why on earth are all my ports being blocked?
  8. Is your computer connected directly to the cable mode without a router?

  9. Yes sir, I took my linksys router out of the loop as mentioned in my original post. What shall I check next?
  10. Post the output from ipconfig/all.
  11. Here you go Grumpy, thanks a lot for the help, I really would love to get this working, it's more about the principal now, it's been kicking my ass for 4 days....

    Microsoft Windows XP [Version 5.1.2600]
    (C) Copyright 1985-2001 Microsoft Corp.

    C:\Documents and Settings\Compaq_Owner>ipconfig /all

    Windows IP Configuration

    Host Name . . . . . . . . . . . . : Home1
    Primary Dns Suffix . . . . . . . :
    Node Type . . . . . . . . . . . . : Hybrid
    IP Routing Enabled. . . . . . . . : No
    WINS Proxy Enabled. . . . . . . . : No

    Ethernet adapter Local Area Connection:

    Connection-specific DNS Suffix . :
    Description . . . . . . . . . . . : Realtek RTL8139/810x Family Fast Eth
    ernet NIC
    Physical Address. . . . . . . . . : 00-15-F2-22-D1-03
    Dhcp Enabled. . . . . . . . . . . : Yes
    Autoconfiguration Enabled . . . . : Yes
    IP Address. . . . . . . . . . . . :
    Subnet Mask . . . . . . . . . . . :
    Default Gateway . . . . . . . . . :
    DHCP Server . . . . . . . . . . . :
    DNS Servers . . . . . . . . . . . :
    Lease Obtained. . . . . . . . . . : Monday, January 05, 2009 6:23:38 PM
    Lease Expires . . . . . . . . . . : Monday, January 05, 2009 7:23:38 PM

    C:\Documents and Settings\Compaq_Owner>
  12. Who do you have for cable internet service?
  13. Metrocast cable, I've been using their tools on their website.. dslreports.com. I get pretty good download speed averaging 6.5mb/s. According to them, and what I've read, my Surfboard modem doesn't do any NATing so that's not the problem. Still searching and reading, thanks for your help, I think we're close.
  14. is a private IP address. If You can see Your public IP online and it is different than modem id oing NAT/ Routing.
  15. What do you get from http://www.whatismyip.com/?
  16. According to their Internet connection answers:

    XP/2000 users

    To refresh your IP while PC is running:

    Click Start, then Run, then type in the box "cmd" and then click OK to open the command-line window.

    Next type "ipconfig /release" then hit Enter. The IP address should read

    Now type "ipconfig /renew" and hit Enter. Now the IP address should read 65.175.x.x OR 192.168.x.x if you are behind a router.

    So you IP address should start with 65.175.X.X.
  17. Hey Grumpy, yea I did that a couple days ago, resets it to then renews back to Why I have no idea, I have NO router in place, connected directly to my cable modem. I remember back when I use to game online I would get my IP using ipconfig and I always got a public IP, not anymore. When I use on of the IP recognition sites I do have an IP on 65.175 network, and it's always the same. Does this shed any light?

    I guess my modem is NATing?
  18. What happens if you open a web browser and enter
  19. THAT'S IT!! I can't believe it, rather embarrassing. My Vonage box sitting right next to my cable modem and completely forgot it was even in the loop. Geezus 4 days to figure that out. What I'm very surprised at is the fact that after working w/ my ISP for 2 days no-one thought to ask if I was using a VOIP service? Evidently that damn vonage box is blocking everything, it's a Motorola model but I can't seem to get logged into it.

    Grumpy, can I hook my router back up and plug my vonage into a router port so it doesn't affect my PC at all or will it not work setup like that?

    Man, thanks alot Grumpy, owe ya cold brew for sure.
  20. Yes, you should be able to plug the Vonage box into the router.

  21. Yep, got it working. got my router back inline as well with my tcp port forwarded and working. The help files in the router state that when using port forwarding you need to setup a static ip address, which I did not do. I just used the that my PC is showing now. Is that IP prone to changing depending on whose connected to my router and such or can I leave it the way I have it now? Not to clear on the static IP setup, or why I would need to do it... Thanks again!
  22. You should use a static IP address that's outside the DHCP range since your Dynamic IP address can change.

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