LAN Network BUG?

[NeedForHelp]

Sirs and Madams;

I'm a newbie and I need help.

We got laptops in our home. We are connected by ADSL modem provided by the ISP which is connected to another ADSL modem/router with four ports for LAN connection. The first ADSL modem has only one port, so I connected it to the another ADSL modem which has four ports.

Phoneline -----> 1st ADSL modem --------> 2nd ADSL modem with four ports ----------> ----> -----> -----> laptops

One laptop is running in Windows Vista Home Basic
Another laptop is running in Windows XP SP2

Here is the problem:

When we are playing games through LAN Connection, some problem or bug occurs. In the game (Dungeon Siege II), when the 1st laptop (Vista) is creating or hosting the game, the 2nd laptop (XP) cannot join in. But, if vice-versa, the 1st laptop (Vista) can join in the game hosted by the 2nd laptop (XP). However, 1st laptop disconnects in a matter minutes.

In another game, (Battle Realms WOW), both laptops can create or host a game and the other can join. However, in a matter of minutes, with no error dialogs that pops out, we can noticed that we are no longer connected. In the screen of the 1st laptop, the 2nd laptop's characters did not move. Same goes in 2nd laptop, 1st laptop's characters did not move.

But, in sharing files, there is no problem. We can share files as much as we want. But in gaming... something is definitely wrong.

Is it because of a bug?

I'm just wondering cause we cannot play decently LAN games in our laptops. Not just that two games mentioned above.

Please HELP us. Please give me steps to destroy this bug. Any suggestion will help.

Thank you...

[YeOldeStonecat]

Sounds like an issue from using 2x routers..creating a double NAT situation. You only want 1x router/gateway on your network.
Use a switch connected to your primary router if you want to add more computers using ethernet, or add an access point if you want to add wireless
Or reconfigure your ISP supplied gateway to run as a bridged modem only...and have your own router do the PPPoE and NAT.

[NeedForHelp]

ALAS... I'm waiting for a reply.

Thank you.

Um... let me try to decipher first what you told me...

[NeedForHelp]

I can't configure the ISP supplied router, it seems that they block the web configurator. I'm planning to press the reset button of the ISP supplied router but I'm wondering if they set something in the router that only them knows for me to connect to the web. Because the router's manual says so, if I can't access its web configurator. Is it safe to press this button? Beca