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Thu Jan 17, 2019, 06:38 PM

Weird....changed to a new cable modem today and about 4 sites I can't connect to......

LOL...one is my Internet provider,COX. Of all my links there are four on this computer which won't connect--this comp is connected with a Ethernet cable. If I use a laptop (wireless) I can connect to them. Any networking peeps ever experienced this??

Using Win10 64 and Firefox,linksys router.

I've tried shutting off ad blocker,cleared out cookies and log ins...blah,blah. Beats me,I've replaced modems before and never had this happen.

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Reply Weird....changed to a new cable modem today and about 4 sites I can't connect to...... (Original post)
Bengus81 Jan 2019 OP
better Jan 2019 #1
PJMcK Jan 2019 #4
better Jan 2019 #7
Bengus81 Jan 2019 #5
better Jan 2019 #8
yonder Jan 2019 #6
walkingman Jan 2019 #2
htuttle Jan 2019 #3

Response to Bengus81 (Original post)

Thu Jan 17, 2019, 06:46 PM

1. Open a command prompt

By typing CMD in the start search box and pressing Enter.
Type IPCONFIG /FLUSHDNS and press enter.
That will clear your DNS cache.

Then type PING {url of site not working} and press Enter.
If it resolves to an ip address (###.###.###.###), then DNS resolution is working. If not, go to network adapter properties, TCP/IP v4 properties, and make sure it's set to retrieve both IP address and DNS servers automatically. Or you can manually set Google's 8.8.8.8 or CloudFlare's 1.1.1.1 as your primary DNS.

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Response to better (Reply #1)

Thu Jan 17, 2019, 06:53 PM

4. Wow

I use Macs and have never had to do anything remotely like that.

Your knowledge is impressive, better.

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Response to PJMcK (Reply #4)

Fri Jan 18, 2019, 10:21 AM

7. Thanks, but really its just a function of exposure.

You probably blow me away with knowledge about macs.
Last one I used was a Mac Plus with 4 MB of RAM.

Yes, MB, not GB.
I'm oldish!

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Response to better (Reply #1)

Thu Jan 17, 2019, 07:24 PM

5. Gawd....yep that worked. Who the HELL would know that of us non-network peeps??

My COX site wouldn't load,YouTube TV and two other sites including PC Partpicker. Why the hell just those and not the other dozens of sites??

Thanks!!

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Response to Bengus81 (Reply #5)

Fri Jan 18, 2019, 10:40 AM

8. There are a number of possible reasons why.

To best understand them, it's helpful to understand what DNS is and how it works. DNS stands for domain name system, and it basically acts like your contact list in your phone. You click on Bob, the phone dials Bob's phone number. Everything in a network works on IP addresses, and DNS translates the easy to remember domain name google.com to the less easy 172.217.11.46 that's the actual IP address that listens to requests directed to google.com.

I'm explaining this from memory, so forgive me if I get something slightly out of order, but in a nutshell, the order of operations is something like this:

1. The local hosts file (c:windows/system32/drivers/etc/hosts) is checked, and returned if found. (This is useful for example when the resource you are trying to access is on your internal network, so you want to use that IP address instead of the public IP address returned to the rest of the world that is not inside your firewall.)

2. The local DNS cache is checked. If the answer is present and still considered fresh, it gets used.

3. The primary DNS server configured for the network adapter is queried. It either returns a fresh cached entry or queries upstream.

The most likely answer for why a small number of sites didn't work would probably be one of two things. Either your DNS resolution was not working and those sites' cache entries were stale, or DNS resolution was working, but those sites' IP addresses had changed, but your cached resolutions were now wrong, but were not yet stale.

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Response to better (Reply #1)

Thu Jan 17, 2019, 07:50 PM

6. I am damn impressed

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Response to Bengus81 (Original post)

Thu Jan 17, 2019, 06:47 PM

2. A little more information - please

Are you saying that you can connect with the laptop with wifi but can't connect on desktop with hard-wired ethernet?

Can you connect to anything on the desktop or just no internet?

On the link failures what is your error message?

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Response to Bengus81 (Original post)

Thu Jan 17, 2019, 06:49 PM

3. Here's a shot in the dark that might almost be the cause

If your old cable modem didn't handle IPv6 (it's a newish network thing), and your new one does, it's possible that your desktop computer is trying to connect to a non-IPv6 site, or via a network path that doesn't support it. And then on the other computer that works through the same modem, it isn't trying to use IPv6.

I think it is enabled by default for Win10. To check (and/or to try disabling it), here are some steps I found for Win10 (note: I'm a unix guy, not a windows guy).

https://medium.com/@JockDaRock/disabling-ipv6-on-network-adapter-windows-10-5fad010bca75

Now, I've never ever heard of someone actually having this problem, since I think the whole notion of routing two different addressing protocols is supposed to deal with pieces of a route not supporting IPv6, I'm not sure it's not possible. And it would be easy to test (just turn it off, and see if you can get to the websites).

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