Can't connect Windows 7 to different Internet connection

Question

I have two internet connections at home - one ADSL (via TPLink ADSL 4port router), one cable, and two computers - PC and laptop.

PC can connect to Internet via ADSL, but it can't connect via cable (Laptop can with zero issues)

These are type of networking I tried:

Thomson (cable) to ADSL router, PC and laptop from router: only laptop connects to internet (tried switching up the connections on ports with no luck) Thomson directly to PC - no luck (when in Laptop the Internet works). Diagnostics (When everything is connected to ADSL router):

Laptop got public IP, PC got 192.168.1.2 Laptop has public gateway/DNS IPs (in ipconfig), PC has all pointing to router (192.168.1.1) PC can ping laptop via ipv6 only (ping -6), the ping -4 doesn't work since the IP of laptop is public IP, and PC can't ping any internet address. When pinging from PC to some internet address by IP the response is:

Reply from 192.168.1.1: Destination host unreachable.

When pinging by name (eg. www.google.com) the response is could not find host ... When cable is directly in the PC, some general error when pinging is reported.

I'm all out of ideas (the troubleshooter didn't help of course), so any idea might be appreciated.

Both computers are Windows 7, the only (maybe significant) difference for networking is that on PC I have installed VMware (but I've disabled all of it's networks, and uninstalled it's bridging on the Local Area Connection).

Answer 1

Normally DSL requires you to use PPPoE to "dial-up" to the internet and the device performs the dial-up will get the public IP. Cable normally just uses plain DHCP, but if you enable bridge mode/disable routing, one of you devices will get the public IP as well.

It seems the problem is, you're not using NAT and the first device to connect to your ISP wins and get the correct IP configurations. The other device were rejected because you can't have 2 IPs on one line and somehow got a private IP instead. You'll have to check the settings on your ADSL router, especially the "WAN" settings.

Note that most home routers are not designed to handle two internet connections (thus two default routes, etc.), in which case you may have to do some manual setup.

One option is to setup a static routing table to direct traffic to the best link (DSL or cable). Thus all your devices get the combined bandwidth and redundancy. The problem is, this table might require a lot of time and pinging to setup and not all routers support this. If yours support SSH or telnet, you may be able to automate this through a script.

The simpler option is to share the cable connection through NAT and put the ADSL on bridge mode. Thus both devices can use the cable link and one device can use PPPoE to dial-up the DSL link and get the extra dedicated connection.