No connection when not going thru router. Why?

[Beer_Cayse]

Three times in the last 4 months I've had crappy connection speeds and have called for Tech Support form Time-Warner - RoadRunner.

I have a wired network with each PC (mine, son and wife) each going to a port on a 4-port router then the router goes to the cable-modem. The router is about 2 months old - I replaced that when I determined a port was bad on the old one.

The cable-modem I have now is new (to me) on July 19th. Each time I have called, one cycle of tests needs to be a PC (mine usually) connected directly to the modem. When I do that, Windows reports no connection but if I flip it back to the router, connection is restored.

The system is powered off during the changeover. I've tried using IPCONFIG to establish connection ... no success.

Specs:
MOBO: Gigabyte MA78GM-US2H
CPU: AMD Athlon XP dual-core 3.0 ghz
RAM: 4 GB DDR2 800 RAM (2 x 2GB)
VIDEO: nVidia GeForce 8400GS - PCiExpress x16 - 512 MB
HD #1: Western Digital 320 GB SATA
HD #2: Western Digital 320 GB EIDE w/SATA converter
** drives are NOT in any RAID configuration
OPTICAL 1: LiteOn DVD/CD combo (burner) - IDE master
OPTICAL 2: LiteOn CD/RW (burner) - IDE slave
CASE: Raidmax Smilodon 500w
KEYBOARD: Logitech G-15 Gaming keyboard (3 banks 18 macro keys) - USB
MOUSE: Dell optical mouse - USB

OPER SYS: XP/SP3 patched thru Aug 23rd

So - any idea why I cannot attach directly to the modem at all? Thanks.

 

[IanJames]

Does your cable company require a specific MAC address to allow a connection? Maybe your router has the MAC address recognized by the cable company and your home pc does not?

 

[Shamus Turlough]

This. Most cable internet modems use MAC address authentication to establish an internet conenction. The way around this is to let the modem sit powered off for about 10 minutes in between changing what is plugged into the modem. This will clear the "remembered" MAC address.

 

[Beer_Cayse]

If you're referring to a static IP, the answer is yes - ISP can set one up, but no I do not use one. It's a dynamic IP.

 

[Beer_Cayse]

Ten minutes, huh? Most I've waited is about 1 minute. The modem I have ia battery backup so powering it off also includes removal of the battery. What a pain in the butt!

I'll remember the 10 minutes tho ...maybe that's what the issue is. Thanks!

 

[Gilmour]

first tip.

go to a dospromt and type

ipconfig /flushdns

also check your pc ip settings, depending on windows you get to them a bit differently, but in control panel should be a network connections thing, right click -> properties.

is ip, gateway and dns configured?

 

[Harlequin]

This. Most cable internet modems use MAC address authentication to establish an internet conenction. The way around this is to let the modem sit powered off for about 10 minutes in between changing what is plugged into the modem. This will clear the "remembered" MAC address.

This is what I guess the issue is as well. I have to do the same thing when I switch to direct connection for testing.