10 Replies Latest reply: Feb 10, 2013 9:36 PM by SwankPeRFection
digistrat Level 1 Level 1 (0 points)

We are visiting a beach house and have about a dozen iDevices that all connect sucessfully via WiFi to Mediacom broadband via a Cisco DPC3825 cable modem. Only a 2008 MPB with 10.8.2 will not resolve DNS lookups.

 

A 2011 MBA also with 10.8.2 works fine. The MBP is configured with the exact same DNS servers. The MBP gets an IP address and I can ping any IP address but Lookup fails using the network utility. I can get an IP address on the MBA and surf it directly by entering it into Safari on the malfunctioning MBP. I tried changing the DNS server to 8.8.8.8 but no joy. Also have flushed the DNS cache. This is the strangest Mac networking problem I have seen in some time. Anyone have any suggestions?

 

Thanks

  • 1. Re: 2008 MBP DNS issues Wifi and DPC3825
    SwankPeRFection Level 4 Level 4 (1,435 points)

    Plug in and see if another network interface on the laptop behaves the same way.  If you manually configure a DNS on the laptop in the currently connected interface, there should be no issues with it resolving.  Also, try Level 3's DNSs instead. 4.2.2.1 and 4.2.2.2 and see what you get.  This will probably end up being one of those strange .plist issues with the part of OSX that drives network control.  Seems weird that OSX has so many networking issues that get resolved by deleting config files to restore to default but there's no GUI way to do so via user settings.

  • 2. Re: 2008 MBP DNS issues Wifi and DPC3825
    digistrat Level 1 Level 1 (0 points)

    Swank,

     

    Thanks for the suggestion. I tried the Ethernet port and it does not even get an IP address but have no way to confirm that the ports on the Cisco box are functioning. Also I was able to connect via the personal hot spot mode on my iPhone so I know the MBP does actually work with other WiFi. Setting the DNS to the level 3 addresses did not help. Very strange.

  • 3. Re: 2008 MBP DNS issues Wifi and DPC3825
    digistrat Level 1 Level 1 (0 points)

    One more data point - I got the same results with Ethernet - gets IP address and I can ping any hard address but no DNS. Must be something odd with the Cisco cable modem. MPB owner reports it works on lots of othe WiFi networks and again I checked and it works fine via the hotspot on my iPhone 5.

  • 4. Re: 2008 MBP DNS issues Wifi and DPC3825
    SwankPeRFection Level 4 Level 4 (1,435 points)

    Are the IPs you're getting private or public?  Are they 192.168.x.x, 10.x.x.x, etc. or are they all public?  Either way, it's probably that Cisco modem/router.  Would be nice ot see what the config on it is.

  • 5. Re: 2008 MBP DNS issues Wifi and DPC3825
    Shootist007 Level 6 Level 6 (16,640 points)

    Turn the Firewall off on the MBP, that is if it is on, and see if you can connect.

     

    If you are running any other Anti Virus, Malware or internet security programs turn them off or uninstall to test.

  • 6. Re: 2008 MBP DNS issues Wifi and DPC3825
    digistrat Level 1 Level 1 (0 points)

    Firewall is definitely off, no antivirus  and its getting private (192.168.x.x) addresses. I can log into the Cisco rounter and all the config is completely standard - there is a firewall in it but its only set to block floods and anonmyous IP requests.

  • 7. Re: 2008 MBP DNS issues Wifi and DPC3825
    Shootist007 Level 6 Level 6 (16,640 points)

    Sorry I must ask.

     

    This Mac was/is working perfectly on some other LAN?

     

    Is it set to use any Proxies?

     

    EDIT:

     

    Have you tried different browsers? Sorry I don't remember if you said that is was or wasn't.

  • 8. Re: 2008 MBP DNS issues Wifi and DPC3825
    digistrat Level 1 Level 1 (0 points)

    Shootist007,

     

    No problem with questions - all help is graciously appreciated.

     

    Yes - the owner reports it works fine on other WiFi and it works fine connected to my Iphone with the hotspot on. No proxies anywhere. Damndest thing I have seen and I have been a Mac user since the dark ages. Other users in the house have mid 2009 MBP with Leopard, three iPads and a 2011 MB air all working fine via WiFi! If it was my Mac and at home would be considering re-installing MLion.

  • 9. Re: 2008 MBP DNS issues Wifi and DPC3825
    Shootist007 Level 6 Level 6 (16,640 points)

    I'm at a lose. A setting on the router to Block Internet access for certain IP addresses? Try Assigning a static IP outside the DHCP Pool range of the router but still in the routers address range.

     

    You said it also didn't work connected by Ethernet? When you did connect it by Ethernet cable did you turn the WiFi off on the Mac (Just to make sure it still wasn't using the WiFi IP and being blocked).

  • 10. Re: 2008 MBP DNS issues Wifi and DPC3825
    SwankPeRFection Level 4 Level 4 (1,435 points)

    Nothing is blocking his traffic.  The fact that ping works by IP and not by name indicates that DNS client service is not working properly on the Mac in question.  I bet that's your problem.  Unfortunately, I don't know how to tell you to fix that, but that's probably the best place to start looking.  If this was a Windows machine, I'd have you check the winsock stack and do a reset as well as check to make sure DNS Client was started as a service.  **** if I know where in OSX this functionality is.  That's what ***** about OSX... they don't give you a lot of control over stuff like this and when it breaks, it's not easy to fix or even check if things are working since everything is via plists and damons, etc.

     

    I would check in Activity Monitor if mDNSResponder is listed as a process.  If it isn't, then that's your issue.