[Macworld]

Post your comments for Mac troubleshooting: What to do when you can't connect to the Internet here

[rmigneron]

Hi,

What about IPv6 ? For those of us who are fortunate enough to have a modern Internet provider worthy of the 21st century :-)

Guys, sites are now more and more using IPv6 (ipv6.google.com for example, sometimes a lot faster !), so you should also verify your connectivity using this protocol. There are loads of test servers out there that can verify this. This one for example : http://www.test-ipv6.com/

Furthermore, OpenDNS provides IPv6 DNS servers too.

Your list of DNS Servers, should be the following :

208.67.222.222
2620:0:ccc::2
208.67.220.220
2620:0:ccd::2

or if your prefer using IPv6 :

2620:0:ccc::2
208.67.222.222
2620:0:ccd::2
208.67.220.220

Cheers,

Ritchie

[rmigneron]

I have to add : www.v6.facebook.com !!!

[Netsynergy]

One important thing you need to remember about using outside DNS sources such as OpenDNS, Google DNS etc. is these are fine when your ISP go down or are faulty, but it's suggested that you return to your ISP DNS address once everything back functioning correctly. the reason being that a lot of websites, streaming services including iTunes all use CDN networks to take the load off of their servers and put the content you re accessing as close to you as possible for maximum performance. The CDN network use your ISP DNS server IP addresses to locate where in the country you are located and then picks the closest servers to you to deliver the content you are requesting. When you use these "outside" DNS servers which are generally located in another part of the country, CDN networks will connect to the closest CDN server to that DNS server which could halfway across the country hence possibly giving you graded performance such as slow website access, streaming videos that are constantly buffering etc. CDN Content Delivery Network.

[jhorvatic]

Another trick which I find works a lot of the time is to reset your location setting in the Network System settings. This setting is like a cache file for the networks you have been on. Sometimes this cache file gets corrupt causing either slow or no network connection even though it may show a correct IP address. To reset it just click on the Location, the menu will pop down giving you an edit locations button. Click on that and you will see Automatic listed and maybe you already added a personal location like home or work. Add another location with the plus button and call it anything you like. Don't forget to click apply. I also like to use the gear with the down arrow next to it under where you see your wireless and ethernet settings to set the service order. If you use WIFI all the time you can move the airport wifi to the top of the list. This makes WIFI come up first and a little faster for it to do so. Click on apply and then check for an internet connection using a browser.

[technologist]

Yet another ill-considered graphic on a Macworld article.

If you can get a 404 error, you do not have an Internet connection problem. 404 errors are generated server-side; if you can see one, your connection and DNS are fine.

[tln1ltj2]

What about when all that doesn't work and it turns out to be essentially a start-up conflict. I found that very problem. Apple Care had be do all those things mentioned, including reinstalling Mountain Lion from the Recovery drive and a second time after erasing the drive via the Recovery option for a totally clean install, then migrating from TimeMachine. Turns out a much easier diagnosis would have helped and saved a lot of time. Use the SafeBoot option. If you can then connect to the Internet it is not your machine, but rather an app/start-up conflict, many of which you might not even be aware of as they don't show up on Log-In items. Then a clean install and a recovery of only documents from Time Machine and a one-by-one reinstall of apps did the trick. Not all apps did get installed as a local service tech informed me that Norton Utilities provided provided by my ISP (Comcast) and MacKeeper were notoriously bad news even though I had been using them for quite awhile without problems. And there were other apps I forgot I even had so I didn't reinstall those. In the end, it all works, but it reminded me of when prior to OSX, there were routines to find out which startup app was causing trouble. I don't know which one was causing the trouble, but the seemingly old school approach, thanks to the technician (not AppleCare) has me back up and running.

[iphonesintocash]

Nudging the wifi is a great way to explain it. Sometimes you just have to give it a tap on the shoulder.

[jeffeyer]

What about a wired router? Sometimes, I see no numbers on Network for the router such as Router, DNS Server, and Search Domains. The status was green. I had to restart my computer which went back to normal, but I don't like to restart it. Log off doesn't wake up my router. There is no software to wake up my router.

[mschmitt]

Step 4.5 should be to reset the device that connects to the Internet, such as a stand-alone cable modem.

[JoeKissell]

Quote

Hi, What about IPv6 ? For those of us who are fortunate enough to have a modern Internet provider worthy of the 21st century :-)

I'm not fortunate enough to have such a provider :-(. (But they say they'll be rolling out preliminary support in 2013.)

I suspect that at the moment, very few people having trouble connecting to the Internet can blame IPv6 problems, but that could be much more true in a few years.

Joe

[murrayE]

You omitted a solution for a not-so-uncommon situation where hard-wired connection through a router to the Internet fails to connect after you wake the Mac from sleep: Open Terminal and then successively give each of the following commands:

sudo ifconfig en0 down
sudo sleep 10
sudo ifconfig en0 up

This seems to be the only reliable way of restoring the connection (short of doing a restart) under such circumstances.

[Panglos]

Quote

One important thing you need to remember about using outside DNS sources such as OpenDNS, Google DNS etc. is these are fine when your ISP go down or are faulty, but it's suggested that you return to your ISP DNS address once everything back functioning correctly. the reason being that a lot of websites, streaming services including iTunes all use CDN networks to take the load off of their servers and put the content you re accessing as close to you as possible for maximum performance. The CDN network use your ISP DNS server IP addresses to locate where in the country you are located and then picks the closest servers to you to deliver the content you are requesting. When you use these "outside" DNS servers which are generally located in another part of the country, CDN networks will connect to the closest CDN server to that DNS server which could halfway across the country hence possibly giving you graded performance such as slow website access, streaming videos that are constantly buffering etc. CDN Content Delivery Network.

If, for example, a user in Dallas connects via Comcast, the user will be connected to an East Coast server whose location Comcast never discloses. If that user uses OpenDNS, the user will be connected via anycast routing to a server in Dallas.

Most any OpenDNS user should be able to debunk claims of slow website access, buffering videos, and so on. Users can and do switch to OpenDNS to improve performance on a permanent basis.