****HELP****

Hello I am new to the forums, and have been wracking my head over this issue for a week now, any help would be greatly appreciated. I will start with my setup. I have AT&T U-verse which comes with a router/modem, and is disabled because I use the ASUS RT-N12 router for home wireless. Im using Ubuntu 12.04 and when installing OpenSSH with Cygwin and connecting to my Windows desktop using the Local IP address everything is fine, but when trying to SSH using the external IP the connection times out. Just for the record, I have tried port forwarding 22 to the local IP of my machine, but still nothing. I am not sure if my sshd_config file is incorrect, or what is going on but outside my LAN I cannot SSH into my windows desktop, which is much needed for my Systems Admin job. What am I doing wrong here? Thanks in advance!!

You need to check the firewall rules on router and Windows - and don't forget to tell what Windows version you're running!
Also you need to be more clear about your setup.
AT&T U-verse is disabled - what is that, is it disconnected completely or is it actually your internet gateway?
ASUS RT-N12 is used for wireless - how?
We need to see a network map here.

So please post NAT (port-forward) rule, firewall rules on router, network map & Windows firewall rules.
(Windows fw-rules might be difficult to get a good printout from.)
Most important to begin with is network map & NAT rule.

I have Windows 7 64bit running on my desktop, my laptop has ubuntu 12.04 along with a Windows 7 partition. The AT&T router/modem is acting basically as a switch and network storage space over ethernet, but it has wireless capability that has been disabled in the router settings. The ASUS router is hooked to the AT&T router/modem via ethernet chord. I have a wireless connection to the ASUS router with my desktop. I have tried port forwarding on the ASUS router, I have added an SSH exception in the Windows firewall for allowing SSH port 22. I can SSH into my Windows desktop with any system on my home network (ASUS router) but when trying the external IP, connection timeout. Not sure why LAN works but WAN doesn't. Sorry im new at this.....

AT&T is a US telephone company and U-verse is their network suite that includes TV, phone and Broadband Internet services.

How are the two routers connected? How is the ASUS LAN/WAN configured? If you are connected to the WLAN port of the ASUS then I suspect you have a double NAT. If you have the ASUS configured for the same network as the U-verse then it may not know how to route traffic.

I've never had to mess with a U-verse router yet but I believe they can be configured in bridge mode. I also don't know how that affects TV, phone or storage. Bridge mode in a nutshell just passes traffic i.e. no NAT, no firewall etc. So your ASUS will work as if it was directly connected to a MODEM.

http://scottworldblog.wordpress.com/...rport-extreme/

Thank you very much, I was thinking double NAT. Yes, the ASUS router is connected to the AT&T box which is also a router/modem combination in the ethernet port. I will try just using the AT&T box alone and see if it works then. I just assumed that disabling the wireless capabilities on the AT&T box it would be ok, guess not.

michaelk:

Please let me know what you need in order for me to figure this thing out. I have Windows configured correctly, at this point it is just the router. I have port 22 forwarded, but I can send you screenshots of my router config, or whatever else you would need. I have given up at this point as I don't know what else to try. I appreciate the help man!!

What is the make/model of your AT&T MODEM/Router? I assume it is a 2Wire.
Did you try just the AT&T box alone?
Is port 22 forwarded on the AT&T box to the correct IP?
Are you using static IPs or have the router configured to reserve the same IP?

http://www.att.com/esupport/article....id=Tt7S7v6RFa1

Yes that is exactly what my router/modem config looks like, and that is the exact process I followed. I will post a screenshot of the AT&T and ASUS router config...Also, I have not tried to connect with only the AT&T router because that is not how I have it setup, even if it works, I will have to plug the ASUS router back in.

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I would disable Windows Firewall and then try to SSH.
If that didn't work then there is a problem with the Router config.

99.999% probability of a double NAT. Turning off wifi does exactly that, turns off wifi, it does not change the fact that the AT&T router is still a router. There may be a setting to make it a bridge instead, but unless you've found/set that option, it's not going to be the default.

Not that that's a problem, but you'll need to configure the port 22 forward in BOTH your ASUS router AND the AT&T router. The AT&T router needs to forward port 22 packets to the ASUS router, and the ASUS router needs to forward them to your Windows box.

What you should do to confirm is just check your IPs.
What is your Windows box's IP?
What is your ASUS router's LAN IP?
What is your ASUS router's WAN IP?
What is the result of going to www.whatismyip.com?

You don't have to post all of the real numbers here, just change them if you're concerned about security. If the ASUS router's WAN IP is not the same as what you get from whatismyip.com, then you have a double NAT.

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You need to explain how the two routers are wired together and configured. What function does the Asus perform?

I assume you have a wire from the AT&T box to the WAN of the Asus. The Asus will get a WAN address via the AT&T DHCP. The ASUS LAN side should be on a different subnet. The ASUS WAN side should be configured with a static IP addresses or reserved IP. The AT&T should forward to the WAN IP then the Asus should forward to the PC IP.

It would be much easier to use the AT&T by it self or configure it as a bridge.