NAPT - requesting explanation and my problem

[Spike]

I'm seeking an explanation of the difference between NAPT and DynamicNAPT if anyone would be so kind. Even if it's no use to me knowing, it's bugging me now. Googleing the term brought up reams of shopping pages etc.

My problem is that using an ART18CX based router, with appropriate port forwarding, I have an application (bit torrent) that seems after a number of hours running to be exhausting my routers NAT tables (at least, it's the most likely (and only) explanation I've found anywhere.) There's no option to flush the NAT tables on the Router config, only to select different NAT modes (NAT, NAPT, DynamicNAPT), of which DynamicNAPT is what I'm using now.

Just in case there's an alternative solution (though I'd rather not change my BT client if it can be avoided - I like the simplicity. ...PML), a post about the problem I've been having that I'd written on my ISP's forum is quoted below...

If I leave Bittorrent running for any length of time, It seems to result consistantly in my normal web browsing and email slowing down considerably, even to the point where images on web pages fail to download, DNS sometimes fails to be resolved, and oppening pages takes forever. (this happened even before traffic shaping changes)

I'm only talking about leaving BT running for around 8-12 hours here before I start seeing these problems, sometimes less. It's not an issue with BT downloading or uploading at rates that max out my connection because BT has been running at full speed during this situation (and it does continue to run at full speed), but it's also been running at half of my line capacity (up or down) or particularly slowly when this happens. the speed at which BT operates does not matter with regards to causing these issues. My Firewall is reporting almost no traffic sometimes, and yet the problem still exists.

Having attempted a HTTP download in this situation, I can say that once connected, the download will come down at a normal and expected speed usually (barring a throttled connection from the remote servers end of the connection), and so it would seem that the problem is with connecting rather than with the speed of the connection to a web server once made.

Restarting the ADSL on the router doesn't fix the issue (and sometimes even results in an inability to re-synch), but rebooting the whole router does. This isn't a general problem with the router, as it can usually stay up under heavy usage for at least 4 days provided I'm not using BT.

Does anybody have any idea of what's going on here? Is it just my connection/service (PlusNet 2Meg Boadband Premier.) or is there something screwy in my setup somewhere..

details:

• 2Mb ADSL connection
• Behind ART18CX Based router with a range of ports (high and low) forwarded, including port 56978 (TCP/UDP) connected via ethernet 10/100
  
• WinXP Pro SP2
• Bittorrent original client 4.1.2 (www.bittorrent.com) set to "look for availiable port:" starting with 56978, with the potential windows TCP stack fix turned on.

 

[RealBlackStuff]

For your router's settings, have a look here:
http://www.portforward.com/english/routers/port_forwarding/Speedcom/ART18CX/ART18CXindex.htm

Why on earth did you obtain such an obscure router?

 

[Spike]

Lol. It was cheap - very cheap. I needed a quick fix to fill a gap, and I've had it ever since.

Cheers RBS. Taking a look now.

edit Ok, shall try it with the settings reccomended there. Wow - 9 ports forwarded - I'm only allowed 20!

It didn't say anything about NAPT though. Would you happen to know what DynamicNAPT is as opposed to NAPT?

 

[Nodsu]

Dynamic NAT and static NAT are the terms you are looking for maybe?

As for BT choking your router, look for a setting in the BT client to limit the number of connections (maybe get a better program if you don't have the option). Set it to something well below 500 and work your way up from there to see what the limit of your router is.

 

[Spike]

Cheers Nodsu.

It's definitely NAPT and DynamicNAPT though. Apparently NAPT is different from NAT. Meh - that's what you get with obscure hardware I guess.

 

[Nodsu]

NAPT is the thing that is commonly referred to as NAT. The makers of your router have decided to use absolutely correct terms (that noone else uses).

 

[Spike]

That'll be Connexant Thanks.