Mountain Lion VPN disconnects internet access

Question

Level 1

0 points

Mountain Lion VPN disconnects internet access

I've recent purchased a Retina MacBook Pro with Mountain Lion pre-installed (10.8, later updated to 10.8.1).

I also own a MacBook Pro running 10.6.8. I have a VPN service on the 10.6.8 MBP that connects me with my work, but also allows a concurrent internet connection to access the rest of the web. No problems there.

On my 10.8.1 MBP, I started with a clean build - nothing was transferred over from the old MBP (no library files, documents, applications, etc...). I created a new VPN service using all the same settings as my old MBP's VPN service. This works and lets me connect to my workplace, as per usual.

However, when my VPN is running, I lose connectivity to the rest of the internet. When my VPN is disconnected, my connectivity returns.

I'm fairly certain I've copied all the network settings from my old MBP to my new MBP, so I don't understand why it doesn't work (VPN AND internet connectivity) as before.

This seems to be a very common problem with Mountain Lion users, and I haven't found a suitable answer to my problem yet. Could somebody please help me with a solution or at least point me in the right direction?

Thank you!

MacBook Pro with Retina display, OS X Mountain Lion (10.8.1)

Posted on Sep 3, 2012 5:34 PM

Reply

Answer 1

robchis Author

Level 1

0 points

Sep 3, 2012 5:56 PM in response to robchis

I should also mention that when connected to my VPN service, I try Network Diagnostics.

The initial screen shows my Ethernet and Network Settings as "Failed", while my ISP, Internet and Server settings all passed.

For "Choose the network port configuration....", I select Wi-Fi and then continue. I then see on the Network Status column Internet dissappear, and Wi-Fi and Wi-Fi Settings appear. Those and Network Settings now all light up as green, and it seems everything in my Network Status column is now passing.

I choose my wireless network on the next page and continue and then recieve the message that "Your internet connection appears to be working correctly."

Yet, when I quit Network Diagnostics and then re-open it immediately again, I find that I'm back to square one with the same status as I first mentioned with Ethernet and Network Settings failing.

What's going on here?😕

Reply

Answer 2

Sep 5, 2012 6:21 PM in response to robchis

Just go on your Retina under the VPN advanced settings and put in Google's DNS 8.8.8.8. That should fix the issue.

Marty

Reply

Answer 3

robchis Author

Level 1

0 points

Sep 6, 2012 4:51 PM in response to Martin De Bernardo

Thanks for the response, Marty, but I tried it and it doesn't seem to make any difference. Have you had a similar problem and used this solution yourself to fix it successfully?

Is there some other aspect that needs to be done? A change in the service order to put my VPN at the top... or conversely have my internet connection at the top of the list? Or should I route all my traffic through the VPN connection? I seems to have tried all these but maybe it's a certain combination that's needed and I'm just missing it?

Thanks again for the help!

Reply

Answer 4

Sep 9, 2012 3:58 PM in response to robchis

You should route all the traffic through the VPN. Yes, that fixed my issues. Try to ping router, server and see if your DNS is working. Ping www.apple.com and then ping 96.16.45.15 to see if you get a response. Try putting the ip address in for Apple and see if Safari shows the page. If yes then it is the DNS for sure.

Reply

Answer 5

hostalp

Level 1

0 points

Dec 27, 2012 3:38 AM in response to robchis

I know I'm resurrecting an old thread a little, but since it's directly related to what I've been dealing with I didn't want to make another thread for the same...

So dealing with pretty much the same (at current test build of 10.8.3) I found out the following.

When you move your VPN connection to the top of the list (Set Service Order) so it will be above your regular connection, or when you select "Send all traffic over VPN connection" in the Advanced options - youll get everything routed through the VPN connection which will in most cases break your internet connectivity (when VPN is connected) and even if not, you'll have an unnecessary overhead in the network path... That's what one would expect so nothing strange here.

However what to do when you want to have both at the same time...

Because of the previous limitations I had to keep the VPN connection down in the list. That let me to use the internet while at VPN, however there was a little problem with the VPN connection - access (to our company machines) by IP address worked for me, however access by hostname (and thus DNS name resolution) didn't.

It seems that in such cases the DNS cache needs to be reset (causing the new DNS resolving order to be enforced) otherwise my client applicatons (SSH, MS Remote Desktop Client) don't know about the new DNS servers that become available via the VPN connection (they appear in the DNS configuration listing but nothing wants to use them).

Once you reset the DNS cache everything starts working properly.

So basically it seems that VPN client in Mountain Lion should do this automatically at the end of establishing the VPN connection, but it doesn't. I consider this to be bug and will try to report it.

There could be some workarounds such as adding the company DNS servers to your default list (/etc/resolv.conf or in the network options) however I didn't try that as I decided to live with IP addresses for now because I don't consider any of these workarounds as very "clean" and it isn't that big trouble for me (for now).

Some resources:

Viewing the current DNS configuration (basically the resolving order): scutil --dns

https://developer.apple.com/library/mac/#documentation/Darwin/Reference/Manpages /man8/scutil.8.html

Resetting the DNS cache: sudo killall -HUP mDNSResponder

http://support.apple.com/kb/HT5343

By the way I'm pretty sure this worked fine in Snow Leopard. The only thing I did differently was that I had my VPN connection at the top of the connections list. Then both VPN and local network + internet worked fine for me.

Reply