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DNS server problems

I went on spring break for a week. Over that week my Macbook Pro (Sep 2012) was turned off and so was the router and modem. When I came back I turned everything on I was able to connect to the router but was not able to get any internet access. I would keep receiving a webpage that said the DNS look up failed.


The part that I do not understand is, my roommates both have macbook pros as well and they are able to connect to the internet without any problems. Also my macbook works perfectly fine when I am anywhere but my home network. It works perfectly on campus, starbucks, and friends places.


If anyone has any ideas of what might have changed it would be greatly apreciated I have no idea how to fix this issue.



We also just got a airport base station and I am still having the same problem.


The problem also occurs if I am pluged in directly or connected over wifi.

MacBook Pro, OS X Mountain Lion (10.8.2)

Posted on Apr 29, 2013 1:08 PM

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14 replies

Apr 29, 2013 10:27 PM in response to 33SuperSport33

Double-click the line of text below to select it, then copy it to the Clipboard (command-C):


www.google.com


Launch the Network Utility application in any of the following ways:


☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)


☞ In the Finder, select Go Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.


☞ Open LaunchPad. Click Utilities, then Network Utility in the icon grid.


Step 1


Select the Lookup tab and paste into the address field (command-V). Press return. Post the output that appears below – the text, please, not a screenshot.


Step 2


Select the Ping tab and do the same. Please enter the same input as you did in Step 1. Don't use the output of Step 1 as input to Step 2.

Apr 30, 2013 8:28 AM in response to Linc Davis

I have a similar problem as 33SuperSport33 except I get no numbers. I tried your method with 192.168.0.1 which I have used in the past and I also tried with 174.29.43.3 which was sent back to me once from my desktop. I also tried with the www.google.com. With the google address ping states: cannot resolve www.google.com: Unknown host. With the numbers it says No route to host.

With lookup it always states ; ; connection timed out; no servers could be reached. Why doesn't my laptop show an IP address? Thank you.

Apr 30, 2013 9:04 AM in response to Linc Davis

This is what came up:




Lookup has started…


Trying "www.google.com"

;; connection timed out; no servers could be reached




Ping has started…


PING www.google.com (74.125.225.241): 56 data bytes

64 bytes from 74.125.225.241: icmp_seq=0 ttl=52 time=45.242 ms

64 bytes from 74.125.225.241: icmp_seq=1 ttl=52 time=66.630 ms

64 bytes from 74.125.225.241: icmp_seq=2 ttl=52 time=43.054 ms

64 bytes from 74.125.225.241: icmp_seq=3 ttl=52 time=41.514 ms

64 bytes from 74.125.225.241: icmp_seq=4 ttl=52 time=41.449 ms

64 bytes from 74.125.225.241: icmp_seq=5 ttl=52 time=41.831 ms

64 bytes from 74.125.225.241: icmp_seq=6 ttl=52 time=50.674 ms

64 bytes from 74.125.225.241: icmp_seq=7 ttl=52 time=45.498 ms

64 bytes from 74.125.225.241: icmp_seq=8 ttl=52 time=41.665 ms

64 bytes from 74.125.225.241: icmp_seq=9 ttl=52 time=43.498 ms


--- www.google.com ping statistics ---

10 packets transmitted, 10 packets received, 0.0% packet loss

round-trip min/avg/max/stddev = 41.449/46.105/66.630/7.349 ms

Apr 30, 2013 12:40 PM in response to 33SuperSport33

Please read this whole message and be sure you understand all of it before doing anything. Back up all data before making changes to your settings.


Write down the server addresses.


Click Cancel to close the Advanced sheet. Unlock the preference pane, if necessary, by clicking the lock icon in the lower left corner and entering your password. Open the DNS tab again and change the server addresses to the following:


8.8.8.8

8.8.4.4


That's Google DNS. Click OK, then Apply.


In Safari, select

Safari ▹ Preferences... Privacy Remove All Website Data

and confirm. If you’re using another browser, empty the cache. Test. Any difference?


Notes:


1. If you lose Internet access after making the above change to your network settings, delete the Google servers in the Network preference pane, then select the TCP/IP tab and click Renew DHCP Lease. That should restore the original DNS settings; otherwise restore them yourself.


2. I’m not advocating Google or anything else as a DNS provider; the server addresses are offerred merely for testing purposes. There may be privacy and technical issues involved in using that service, which you should investigate personally before you decide whether to keep the settings. Other public DNS services exist.

May 2, 2013 6:21 AM in response to 33SuperSport33

Please read this whole message before doing anything.


This procedure is a test, not a solution. Don’t be disappointed when you find that nothing has changed after you complete it.


Step 1


The purpose of this step is to determine whether the problem is localized to your user account.


Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”


While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.


Test while logged in as Guest. Same problem?


After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.


*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.


Step 2


The purpose of this step is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login, or by a peripheral device.


Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. Note: If FileVault is enabled, or if a firmware password is set, or if the boot volume is a software RAID, you can’t do this. Post for further instructions.


Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs. The next normal boot may also be somewhat slow.


The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.


Test while in safe mode. Same problem?


After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of steps 1 and 2.

May 2, 2013 8:22 AM in response to 33SuperSport33

The fact that you are getting DNS lookup failures when browsing the web, yet Network Utility was able to successfully resolve www.google.com as 74.125.225.241 for a ping, is very odd. That (in addition to the fact that nobody else on your network) also indicates that this is not actually a DNS server issue, which is why changing the DNS server settings didn't work.


My guess would be that you have some third-party software that is blocking certain connections and not others. Do you have any kind of anti-virus, internet filtering or firewall software installed?

May 2, 2013 6:24 PM in response to Linc Davis

I was not able to get on the internet with the guest account, I had the same problem that I have been having with my regualr account.


When I did the bootup in safe mode I was able to get onto the internet. In fact I am posting this from my macbook right now which makes me so happy to know that I am finnaly getting somewhere with this problem, espically since my final exams are coming up in the next couple of weeks.


So since I was able to get internet in safe mode, what does this mean, and where do I then go from here.



Thank you so much for helping me with this, we are almost there.

May 2, 2013 7:56 PM in response to 33SuperSport33

Please read this whole message before doing anything.

This procedure is a diagnostic test. It won’t solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

Third-party system modifications are a common cause of usability problems. By a “system modification,” I mean software that affects the operation of other software — potentially for the worse. The following procedure will help identify which such modifications you've installed. Don’t be alarmed by the complexity of these instructions — they’re easy to carry out and won’t change anything on your Mac.


These steps are to be taken while booted in “normal” mode, not in safe mode. If you’re now running in safe mode, reboot as usual before continuing.


Below are instructions to enter some UNIX shell commands. The commands are harmless, but they must be entered exactly as given in order to work. If you have doubts about the safety of the procedure suggested here, search this site for other discussions in which it’s been followed without any report of ill effects.


Some of the commands will line-wrap or scroll in your browser, but each one is really just a single line, all of which must be selected. You can accomplish this easily by triple-clicking anywhere in the line. The whole line will highlight, and you can then copy it. The headings “Step 1” and so on are not part of the commands.


Note: If you have more than one user account, Step 2 must be taken as an administrator. Ordinarily that would be the user created automatically when you booted the system for the first time. The other steps should be taken as the user who has the problem, if different. Most personal Macs have only one user, and in that case this paragraph doesn’t apply.


Launch the Terminal application in any of the following ways:


☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)


☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.


☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.


When you launch Terminal, a text window will open with a line already in it, ending either in a dollar sign (“$”) or a percent sign (“%”). If you get the percent sign, enter “sh” and press return. You should then get a new line ending in a dollar sign.


Step 1


Triple-click the line of text below to select it:

kextstat -kl | awk '!/com\.apple/{printf "%s %s\n", $6, $7}' | open -f -a TextEdit

Copy the selected text to the Clipboard by pressing the key combination command-C. Then click anywhere in the Terminal window and paste (command-V). A TextEdit window will open with the output of the command. Post the contents of that window, if any — the text, please, not a screenshot. You can then close the TextEdit window. No typing is involved in this step.

Step 2


Repeat with this line:

sudo launchctl list | sed 1d | awk '!/0x|com\.(apple|openssh|vix)|edu\.mit|org\.(amavis|apache|cups|isc|ntp|postfix|x)/{print $3}' | open -f -a TextEdit

This time you'll be prompted for your login password, which you do have to type. It won't be displayed when you type it. Type it carefully and then press return. You may get a one-time warning to be careful. Heed that warning, but don't post it. If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator.


Note: If you don’t have a login password, you’ll need to set one before taking this step. If that’s not possible, skip to the next step.


Step 3

launchctl list | sed 1d | awk '!/0x|com\.apple|edu\.mit|org\.(x|openbsd)/{print $3}' | open -f -a TextEdit

Step 4

ls -1A /e*/mach* {,/}L*/{Ad,Compon,Ex,Fram,In,Keyb,La,Mail/Bu,P*P,Priv,Qu,Scripti,Servi,Spo,Sta}* L*/Fonts 2> /dev/null | open -f -a TextEdit

Important: If you formerly synchronized with a MobileMe account, your me.com email address may appear in the output of the above command. If so, anonymize it before posting.


Step 5

osascript -e 'tell application "System Events" to get name of every login item' 2> /dev/null | open -f -a TextEdit

Remember, steps 1-5 are all copy-and-paste — no typing, except your password. Also remember to post the output.


You can then quit Terminal.

DNS server problems

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