I woke up today to find that my internet wasn't working. I checked all the cables, and everything was connected, I tried to connect to my router @ 192.168.1.1 . It didn't connect. I checked the cables over again, I restarted the router, I restarted my computer, nothing was working. I ran ipconfig on the command line, and it said the subnet mask was 255.255.0.0
. I've never known what this is, but every time I've seen it, it's always been 255.255.255.0
, so I opened up my network bridge and set it manually.
Voila! I was able to connect to my router. No internet access yet, but I could also connect to the modem. What was missing was the DNS servers. When I set the subnet mask manually, I had to set everything else manually too. I didn't know any off hand, but I had remembered that when I ran google's DNS benchmarking tool, its tertiary choice was the address of my router. I don't know what this means exactly, but I put it in and it worked.
How does having my router as a DNS server work? Is it using its cache, or is the router using the dns servers that would have been used if I left my computer on automatic? Also, why was my computer saying the subnet mask was 255.255.0.0
? Can I prevent this without setting everything manually?
Setup:
I'm running Windows 7 Ultimate x86
I'm connected directly to an Actiontec (192.168.1.1) router.
The Actiontec is connected to a Linksys (192.168.1.2)
The Linksys is connected to the TW Cable modem.
Best Answer
As Jim G said, a router typically forwards lookups to the IP of the DNS server it is configured for - To add... The benefit of this is that devices can register themselves in DNS so you can access via hostname - this would not work if you only used your ISP's DNS (excluding Netbios/similar).
As for the netmask... networking 101 time!
a netmask literally masks everything before it... For example,
255.255.255.0 can be:
XXX.XXX.XXX.YYY
In the same way as:
255.255.0.0 can be:
xxx.xxx.YYY.YYY
What I mean by this is, the subnet just defines what is on your own network, anything that isn't, requires you to go through the router. By using the range 192.168.1.x on a /24 (255.255.255.0) subnet, simply means that anything from 192.168.1.1-192.168.1.254 is on YOUR network, anything else has to go through the gateway.
By changing the subnet to a /16 or 255.255.0.0 simply means that your network is 192.168.0.0 - 192.168.254.254, but, as these are all private addresses, it really shouldn't make that much difference in a home network.
As to why it suddenly changed, and the fact you are using a bridge, all I can think is that it was either an update to the router/similar that caused problems, or a driver update on your machine.... but, it is an odd one.