So I have a linksys UPnP-enabled router. Behind my linksys router are several machines, one of which is my ubuntu server with ssh installed. I want to be able to get past the linksys firewall via UPnP. The ubuntu server requests a dynamic IP (NAT), so manual port forwarding won't always work. Is there some sort of linux UPnP client that will ask the router to open a port for the requested IP?

The other solution to this problem would to set a static IP on my ubuntu server. But the problem is my ISP's DNS servers change from time to time. Is there a way to request via DHCP (or some other protocol) only the DNS servers and not an IP address?

There is no DNS forwarding option in your router? Some let the router act as dns server for the machines on the internal network...

Externally, I have a dynamic DNS (dyndns.org, I believe), and I run the client on my local computer.  That helps external people get to my network. 

Inside my network, my server-type computer have static ip addresses.  So I use port forwarding to get from the router to the internal system. 

I disabled UPnP, because I don't trust it.  It's one of those scary technologies that most people don't really understand but that is enabled by default, and doing that kind of thing scares me. 

[quote author=Adron link=topic=13505.msg137619#msg137619 date=1134582839]
There is no DNS forwarding option in your router? Some let the router act as dns server for the machines on the internal network...
[/quote]

I looked for this option because I remember being assigned my router's address for DNS servers a few months ago. No option, but I set resolv.conf to point to my router and it worked. So now my ubuntu server has a static ip with the dns settings pointing to my router.

[quote author=iago link=topic=13505.msg137634#msg137634 date=1134586798]
I disabled UPnP, because I don't trust it.  It's one of those scary technologies that most people don't really understand but that is enabled by default, and doing that kind of thing scares me. 
[/quote]

I needed to install UPnP becasue some function with MSN wouldn't work, for example, sound, Whiteboard, Remote Assistance(don't use it that much). I'm also behind a wireless router not of my own from which I am talking the internet.

I like UPnP because it makes things work transparently. Although I agree with it being rather much of a black box. You don't see what ports a certain program requests forwarded in your nat.

[quote author=MrRaza link=topic=13505.msg137725#msg137725 date=1134608895]
[quote author=iago link=topic=13505.msg137634#msg137634 date=1134586798]
I disabled UPnP, because I don't trust it.  It's one of those scary technologies that most people don't really understand but that is enabled by default, and doing that kind of thing scares me. 
[/quote]

I needed to install UPnP becasue some function with MSN wouldn't work, for example, sound, Whiteboard, Remote Assistance(don't use it that much). I'm also behind a wireless router not of my own from which I am talking the internet.
[/quote]

I have the same problem except the UPnP function never seems to kick in. I usually just end up manually forwarding port 3389.

[quote author=dxoigmn link=topic=13505.msg137755#msg137755 date=1134617289]
I have the same problem except the UPnP function never seems to kick in. I usually just end up manually forwarding port 3389.
[/quote]

I meant Functions, but anyway. If you want to install UPnP and use Windows XP/2K or NT for that matter, go to Start then click Set Program Access and Defaults. Go to Add/Remove Windows Componets. When you are in the wizard, scroll down to Networking Services, click details, and check UPnP User Interface. It should install Now. You might need to restart. If your behind a router, Log on using 192.168.1.1, and click on the Applications & Gaming section of that router and go to the Port Range Forwarding Section. Add msn0 and msn1 to the application list and open the following ports for msn0 6901 to 6901, enable both tcp and udp, add your ip address and check enable. For msn1, do all the same except open the ports from 6891 to 6900. All your MSN services should work now.