A networking problem

[Vu Pham]

I need your advice !!!

Recently my home network is pretty slow when accessing the Internet . 
Contacting the ISP's support shows the problem is my Linksys (E3000) 
router. Their tests are:
- connecting the PCs directly to the ISP cable modem ( a Motorola ) 
shows the bandwidth as high as expected.
- connecting the PCs to my router, which connects to the modem, shows 
the bandwidth is pretty low.

So I got another router (E4200) to test but it shows the same pattern: 
slow with router, fast with modem only.

I do not believe that both routers are bad so I install a Linux server 
that acts as a router between the Linksys router and the modem. The 
purpose is to check the packets and bandwidth from the router.

Well, now all my PCs (wireless or wired) behind the Linksys router 
access the Internet as fast as when I connect them directly to the modem.

How can this be ? Some kind of conflicting between the Linksys routers 
and the modem ?


Thanks,
Vu