How to set routing on XP machines with WiFi and LAN

[cryowizard]

I have setup my new PC with a WiFi connection to the cable modem and 100M LAN for internal transfers of large files. The problem was that after a reboot, despite WiFi being connected and up, all Internet connectivity would fail.

It looked like a routing issue, and it indeed was. Apparently, due to how Windows determines the metrics of the interfaces available on the system, the LAN would always win and LAN router would be chosen as a default gateway, instead of a WiFi one.

In my home network, 192.168.2.1 is the WiFi router which is supposed to be the default gateway, and the 192.168.3.200 is the LAN router which is supposed to serve only the hops to the .3 network.

Original "route print" command would yield the following:


Active Routes:

Network Destination	Netmask	Gateway	Interface	Metric
0.0.0.0	0.0.0.0	192.168.2.1	192.168.2.2	25
0.0.0.0	0.0.0.0	192.168.3.200	192.168.3.238	20
127.0.0.0	255.0.0.0	127.0.0.1	127.0.0.1	1
192.168.2.0	255.255.255.0	192.168.2.2	192.168.2.2	20
192.168.2.2	255.255.255.255	127.0.0.1	127.0.0.1	20
192.168.2.255	255.255.255.255	192.168.2.2	192.168.2.2	20
192.168.3.0	255.255.255.0	192.168.3.238	192.168.3.238	25
192.168.3.238	255.255.255.255	127.0.0.1	127.0.0.1	25
192.168.3.255	255.255.255.255	192.168.3.238	192.168.3.238	25
224.0.0.0	240.0.0.0	192.168.2.2	192.168.2.2	20
224.0.0.0	240.0.0.0	192.168.3.238	192.168.3.238	25
255.255.255.255	255.255.255.255	192.168.2.2	192.168.2.2	1
255.255.255.255	255.255.255.255	192.168.3.238	2	1
255.255.255.255	255.255.255.255	192.168.3.238	192.168.3.238	1

Default Gateway: 192.168.3.200


Note that there are two entries for "all hops" - 0.0.0.0 - but their metrics, determined automatically by Windows, are different: the 3.200 LAN router would have a smaller metric of 20 than the WiFi router's metric of 25, resulting in the LAN router becoming default gateway for the network subsystem.

The fix would be to reverse the metrics for those routes.

Fortunately, it's a known issue and Microsoft has an easy way of changing it - KB 894564 (I followed the 'How to change the interface metric on a network adapter' section). The idea is to disable automatic metric determination for the adapters in question and put in values manually. I simply reversed the metric values and it fixed the problem.

The new route print would yield:

Active Routes:

Network Destination	Netmask	Gateway	Interface	Metric
0.0.0.0	0.0.0.0	192.168.2.1	192.168.2.2	20
0.0.0.0	0.0.0.0	192.168.3.200	192.168.3.238	25
127.0.0.0	255.0.0.0	127.0.0.1	127.0.0.1	1
192.168.2.0	255.255.255.0	192.168.2.2	192.168.2.2	20
192.168.2.2	255.255.255.255	127.0.0.1	127.0.0.1	20
192.168.2.255	255.255.255.255	192.168.2.2	192.168.2.2	20
192.168.3.0	255.255.255.0	192.168.3.238	192.168.3.238	25
192.168.3.238	255.255.255.255	127.0.0.1	127.0.0.1	25
192.168.3.255	255.255.255.255	192.168.3.238	192.168.3.238	25
224.0.0.0	240.0.0.0	192.168.2.2	192.168.2.2	20
224.0.0.0	240.0.0.0	192.168.3.238	192.168.3.238	25
255.255.255.255	255.255.255.255	192.168.2.2	192.168.2.2	1
255.255.255.255	255.255.255.255	192.168.3.238	2	1
255.255.255.255	255.255.255.255	192.168.3.238	192.168.3.238	1

Default Gateway: 192.168.2.1

Comments

[rkatsyv.livejournal.com]

Damn.

[cryowizard.livejournal.com]

That's what I said. The freakin' Internet just wouldn't work, and that kinda pissed me off. Creatively ;)

[(Anonymous)]

поддерживаю :)
АС