Safari/Firefox “Site not found” errors

Numerous people have posted to the Apple discussion board regarding “site not found” errors, and web browsers requiring two attempts to load a page:

http://discussions.info.apple.com/webx?14@101.TyczaANxCsQ.1@.689ef4f7

This was REALLY annoying me, so I started doing some digging to see what was wrong. When I broke out tcpdump, I noticed that OS X was sending AAAA record ( these are the IPv6 equivalent to an IPv4 A record ) requests to my DNS server:

$ sudo tcpdump -i en1 -vvvv -n -e port 53

[ … ]

08:51:49.710240 00:0d:93:83:1d:73 > 00:03:ba:05:9d:9f, ethertype IPv4 (0x0800), length 73: IP (tos 0x0, ttl 64, id 29629, offset 0, flags [none], length: 59) 192.168.1.8.49428 > 192.168.1.1.53: [udp sum ok] 20324+ AAAA? www.apple.com. (31)

08:51:49.712412 00:03:ba:05:9d:9f > 00:0d:93:83:1d:73, ethertype IPv4 (0x0800), length 171: IP (tos 0x0, ttl 64, id 20532, offset 0, flags [none], length: 157) 192.168.1.1.53 > 192.168.1.8.49428: 20324 q: AAAA? www.apple.com. 1/1/0 www.apple.com. CNAME[|domain]

Now, why Safari is causing the name resolution libraries to query “www.apple.com” when I visit www.cnn.com is beyond me ( I will have to do some more digging). Since I am on a pure IPv4 network, I tried disabling IPv6 in the network preferences tab to see if it would stop sending AAAA record requests. This was not the case, and I still had trouble loading pages. While reviewing the latest errata on the OpenBSD errata page:

http://www.openbsd.org/errata35.html

I came across the following:

“BIND contains a bug which results in BIND trying to contact nameservers via IPv6, even in cases where IPv6 connectivity is non-existent. This results in unneccessary timeouts and thus slow DNS queries.”

Well hot dog, this seems to align with what I was seeing and experiencing!!!! I applied the patch to my OpenBSD name server, restarted named, and the problem seems to be fixed. Several of the folks on the discussion board also mentioned hard coding the DNS servers, which may or may not fix the issue ( if this is a BIND specific issue, then your ISP will need to patch their servers). Once I get some additional time, I will check to see if this is BIND or OpenBSD specific. Stay tuned!

4 thoughts on “Safari/Firefox “Site not found” errors”

  1. Hi,

    I’m from France as you may imagine with my email address. I looked in a few French speaking chats specialized in Apple products, but I could not find any answer to this question. I’m not at all a professional of computers and internet, but up to now, I succeeded in managing my private home network. I have there a very simple Peabird Wifi router on which I have 2 Macs connected through ethernet wires, and 2 PC laptops connected through Wifi to the router.

    The router is connected to the ISP by means of a DSL cable modem .
    In order to make all these devices run, I had to make such a configuration.
    Router connects through DHCP
    Computers have fixed IP addresses in the Router domain.
    Computers have DNS addresses of my ISP.

    Till a few days ago, everything went well, only the Mac OS X computer (Mini) had sometimes the problem “server could not be found”, but not so frequently. The other Mac, OS 9 operated, an old good 6400 boosted with a Crescendo G3card, works perfectly on the internet using as well IE5.0 or Netscape 6.

    A few days ago, the ISP changed its access configuration, and thus, I changed the DNS addresses on each computer. All of them work well except the Mc OS X one, and now, I have at least half of the internet sites that I cannot reach anymore, Safari saying “server could not be found”. I tried with IE, same punishment. On the French chats, I ‘ve read some posts talking about “time out” problems that were suspected, but without giving a solution.

    Then, when I read your post, I said, Yeah, that’s it. But I picked up the patch (with my old 6400, because the Mini was unable to reach the web page), but as we use to say in French, now I stare at it like a chicken does in front of a table fork.How can I use this patch ? My OS X is Panther 10.3.9. As I said previously, I’m not a computer professional.

    Thank’s in advance for explaining how to install this patch.

    Kind regards.

    Loïc

  2. Hi,

    It’s me again. I have solved my problem. While browsing on Mac discussions, I saw that everybody advises to configure the computers behind a router, as well PCs and Macs, through DHCP instead of giving them fixed addresses.

    I remember that when I installed the router, more than 2 years ago, it did not work, I don’t know why. Maybe my ISP changed its DNS servers configuration. Now, I tested this configuration on the Mac Mini (OS X) yesterday night, and finally Safari reaches the sites for which it used to say “site not found”.

    Bye !

  3. Hey,
    I am having this exact problem i think, but i’m not sure how you would fix it. I opened terminal and tried following the instructions in the patch, but i just got my imac a couple days ago and don’t know enough about the subsystem to be able to confidently do something like this to it. I need all the help i can get. Thanks!.

  4. One of my cleulagoes picked up on my switch to Solaris and told me that it’s definitely worth persevering with Linux (suggesting that Solaris is a dying technology – a comment that I can’t say I really agree with). Anyway, he got in touch with a contact at Novell and a boxed copy of SUSE Linux 10.0 arrived in the post this morning so looks like I’ll be giving that a go too!

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