Router behaviour

[IP_Freely]

I have a problem with my internet connection. The configuration of which is rather awkward, as the phone line goes into a splitter, then one of these goes to a modem, the other to the phone. The modem is also a router, and from this the internet line goes to a wireless gateway, which sends the signal to my computer. Now, when that's cleared up, I might add that the signal is above 80% (excellent).

First of all I would like to know if I even need this ADSL modem/router, or if I could use the gateway only.

Now, the problem occurs when using either MSN Messenger 7.0 beta or any webcam/audio activities in earlier versions of Messenger. I can't use MSN Messenger 7.0 beta for more than about 2 minutes, before I get disconnected, and the only solution is to reboot the modem and the computer, to acquire a new I.P. address. However, I may use MSN Messenger 6.2 for as long as I want, but the minute people for instance try to send me a file, and I click accept, I get disconnected. However, if I press cancel, or ignore the invitation, I stay connected. I also get disconnected when using webcam and/or audio in my conversations.

Now, I've done some research and I believe that the problem can be fixed by opening certain ports (6891-6900), but I do not know how to do this. I tried the knowledge base for my modem/router, but it tells me that there's no such feature, and that I'd have to use the ports that are already open. That doesn't help me much, and to be honest with you, this is not my area of expertise, as a matter of fact I don't know a thing about this.

Another thing, which might affect this, is that I have NAT (Network Address Translation) enabled. To be honest, I don't know what this is, but it seems as though I can't disable it, and I really shouldn't edit anything in my router's configuration utility, as I honestly don't know what I'm doing. But several peer2peer-programs keep warning me about a "NAT-problem" and that I should change my connection settings.

So if anyone could help me solve this problem (or these problems), I would be grateful. As you have probably already noticed, I'm not familiar with routers, gateways or modems, so I appreciate all the help I can get.

Thank you,
I.P. Freely :chk:

 

[Anti-Trend]

...I'm not familiar with routers, gateways or modems, so I appreciate all the help I can get.

Allow me to direct you to our Networking and Security FAQ.

...First of all I would like to know if I even need this ADSL modem/router, or if I could use the gateway only...

First of all, please make sure all the phone jacks in your building have DSL filters plugged into them, except for the one your DSL modem will be plugged into. That one must be plugged directly into the wall with no filter.

As for whether or not you need your modem, it really depends on the capability of your router. If your router has built in ATU functionality (not many do), it'd be a modem/router just like the one you're using now.

Regarding your connectivity problem, your issues are related to double-NATing. :( NAT is "Network Address Translation", which is pretty standard accross all routers. NAT works by basically hiding a whole network behind a single address, so that the only address which is visible is the NAT router itself. NAT isn't so much a form of protection as network simplification (for those inside your network) and obfuscation (to those outside). Because you have one NAT router behind another, you're in a tricky situation for P2P software, especially since you're running Windows (Windows isn't much good in complicated networks). The way I see it, there are three ways you could resolve your issue:

a) Remove one of the routers, thereby simplifying your network
b) If possible, disable the firewall on your wireless router, since its already behind a firewalled router
c) Enable forwarding of routing tables on both routers (although, with poorly-written P2P software this may not solve your issue)

No matter which way you go, you may need to do some port forwarding in order to get your software working properly. Refer to your router(s) documentation for specifics on how to accomplish this. Every router is a little different, so there's no "howto" that covers all routers.

-AT

 

[IP_Freely]

Thank you, Anti-Trend. Still working on the problem, but now I have the three options that you told me.

I'm currently running a third modem (only) and a wired network, which is a temporary solution to avoid this double-NAT problem, while I try to figure this whole thing out.

I really appreciate your help.

Thank you,
I.P. Freely ;)

 

[afidelino]

Hey IP..... whats your router brand, because there are routers that has an issue with MSN Messenger, you have to upgrade the firmware....

 

[IP_Freely]

I had to check whether the problem occurs in the modem/router or in the wireless gateway. When I use a wired network, I get the same problem, which would imply that the problem occurs in the modem/router, as the wireless gateway is not in use.

The modem/router's name is "TopCom Xplorer 871BT". I'll try and see what I can find.

Thanks for your help, afidelino

I.P. Freely ;)