router behind router working but creates problems with video buffering

[Dave]

Hi,

Excellent info on your site so was hoping I could get some help with my router problem. I've added a wireless router (TP-Link TL-WR841ND v3) behind a 2071-A Gateway modem.  I've enabled DMZplus mode on the modem for the router and everything seemed to be working fine.  Internet working on both computers wired to the router and wireless working as well.  But when I try to watch a streaming video on either computer from pretty much any site I get buffering problems.  The video will start fine but will only go for a couple of minutes before pausing for rebuffering.  In the worst case, with sites such as allmyvideos.net, it will lose the connection completely after buffering a couple of minutes worth and have to be reloaded.  I changed back to just the modem and the problems all went away.  Insert the router again and the problems are back straight away.  Download speeds are similar in both configurations (6-7 Mbs) but have noticed that other websites sometimes seem to 'hang' briefly with the router in the loop, but harder to quantify.

Both computers running Windows XP SP3 with Windows Firewall on.  I tried turning the firewall off but it made no difference.  The modem is connected into the router's WAN port and I remember seeing something about connecting to a LAN port but haven't tried that yet

Any ideas?

Thanks,
Dave

[Shane]

Well the fact that you took the TP-Link out and the problems went away show it to be something in the TP-Link causing it.

Of course the fun part is trying to figure out if it is a simple setting or a bug in the router firmware

Does the TP-Link have any firewall settings you can turn off?

Shane

[Dave]

Ding Ding, we have a winner.  Thanks for pointing out the simple horse while I was looking for zebras.  Disabling the TP-Link's firewall seems to have removed the buffering problems.  Now my question is about security as the modem is in DMZ plus mode and the TP-Link has no firewall now.  Does this mean I need to rely on a software firewall?  I've attached a screenshot of the firewall page.  Running a port test shows that with the firewall enabled all the ports are in stealth mode, but with the firewall off many of them show up as closed.  From what I recall that's how it was with just the modem though I think that had fewer ports listed as closed, but there were still some.

Thanks for helping to sort the original problem and if you have any thoughts on the security issue that would be great as well.

Cheers,
Dave

[Shane]

A router is a hardware based firewall even when you have firewall settings off. In fact a lot of routers dont even have options like that. They are nothing more than some extra features.

What makes a router safe is basically port forwarding.
http://www.pcwintech.com/what-port-forwarding-nutshell

You port forward to tell the router where to send a new connect. Otherwise it doesnt know what to do with it so it drops it.

Shane