Internet connection problem

[blaizedm]

My home network consists of 2 computer connected through a router, pretty simple. this computer can obviously connect to the internet, but my other one cannot. it was fine last night, but this morning it wouldnt work. ive pinged the loopback, router, this computer, and the gateway, and they all work fine, but when i try to ping something outside the network, it times out. i ran the network diagnostic, and everything passes except "DNS server search order" and both of the pings it did have timed out. i reset the winsock2 registry and cleared the ARP cache, and when i run the network repair, it says it completed it just fine. if i try to delete the connection from the network connections in the CP, it wont let me (no reason given, "Cannot delete this connection").

any suggestions?

[Will.Spencer]

Originally Posted by blaizedm

My home network consists of 2 computer connected through a router, pretty simple. this computer can obviously connect to the internet, but my other one cannot.

This gives you a useful tool. You can compare the two machines to see how they differ.

Originally Posted by blaizedm

it was fine last night, but this morning it wouldnt work.

That is usually where we start troubleshooting -- by asking what has changed. It appears safe to say that you have not changed anything on that PC, so we look at what else could have occurred.

• Changes at your ISP
• Software changes on that PC (Malware, Windows Update, automated updated from other applications)
• Hardware failure (Network cables, NICs, router ports)
• Spouses, kids, etc...

Originally Posted by blaizedm

ive pinged the loopback, router, this computer, and the gateway, and they all work fine, but when i try to ping something outside the network

That points to a routing issue. What is in your routing table?

You can use the `netstat -nr` command to find out. Do your packets have a route outside your network?

How do the routing tables on the two machines compare?

Or, it could point to a DNS issue. When you issued these `ping` commands, did you use domain names or IP addresses?

You can use the `nslookup` command to test your DNS configuration. Of course, if there is a problem with Layer 1-3 networking, DNS will fail as a result.

Instead, for this purpose, we can rule DNS in or out as a problem by pinging an IP address explicitly. Try the `ping 198.202.74.92` command.

If it works, you have a DNS issue. If it fails, you have an issue somewhere on layers one to three.

Layer one (the physical layer) and layer two (the data link layer) seem to be above suspicion, because you can ping your default gateway.

Do you have a software firewall on that machine that could have updated itself overnight, with potentially bad results? Is that machine free of malware?

I'd say the most likely issue is still DNS. Do the DNS configuration on both systems match? You can see the configuration in the Control Panel and you can see the results of the configuration with the `ipconfig /all` command.

[blaizedm]

well i realized what changed. a couple days before, i had switched to a new cable modem, but then after a few days it needed to be activated so i switched back to the older modem and thats when the problem started. i tried the nslookup thing and it timed out, and when tried to ping the dns server that also timed out. so i did a system restore hoping to cancel anything that wouldve changed on my computer, but it still doesnt work. do you think switching modems might have changed something?

[Will.Spencer]

Can you reboot the cable modem to make sure that it's ARP cache is cleared?

Have you tried any of the other troubleshooting steps which I recommended?

[blaizedm]

i checked the netstat command and everything looked fine (although i admit i wasnt exactly sure what i was looking for, nothing looked weird). when i was doing the ping commands i was using ip addresses. when i tried to connect to something outside my network i would use a domain name (www.google.com). and when i did the ipconfig /all, the settings matched on both computers (other than xxx.xxx.x.100 and 101 for the ip addresses).

im actually writing this post at my schools computer lab so i cant reboot my modem, but ill try that when i get back. i did reset it a few days ago when i first had this problem and it didnt do anything, though.

thanks for your help btw

EDIT- i rebooted the modem and it still doesnt work

EDIT again- fixed it. i dowloaded the macshift program and ran that, works fine now. i guess when i hooked up the new modem, it the MAC settings changed to work with that one, but when it stopped working they never changed back.