On my Mac with OS X Snow Leopard, I continually get "Server Not Found" errors on my web browser (Firefox) while browsing various web sites. In attempts to resolve the problem I've tried the following (each, more than once):
- Reset my router (cut power)
- Reset my cable modem (cut power; Comcast)
- Flush DNS via dscacheutil -flushcache
I can't find what is causing the problem or a different way to resolve it. I have several computers on the router and I don't get this problem with them.
In some cases, only part of the page will load. Graphics might be missing or ads don't load. I'm almost sure it has something to do with DNS but I'm not sure if it might be the Mac or if it is something with the router.
Any thoughts would be appreciated. I'll try any reasonable suggestions...
Update: In response to a request for example sites:
- www.python.org - I noticed it a lot here but I follow a lot of hyperlinks
- My Graduate Schools' sites
It occurs intermittently and I know that it isn't the site because I can quickly access the site on my other computers. Also, if I refresh enough -- 3 to 4 times --, it will usually pull up the site.
Update: Based on feedback thus far, I tried
dig. I was having trouble with Ubuntu.com so I ran the dig on that. Here are the results:
frank-villasenors-macbook:Documents FrankV$ dig www.ubuntu.com ; <<>> DiG 9.6.0-APPLE-P2 <<>> www.ubuntu.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60666 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;www.ubuntu.com. IN A ;; ANSWER SECTION: www.ubuntu.com. 432 IN A 22.214.171.124 ;; Query time: 24 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Tue Oct 27 18:31:33 2009 ;; MSG SIZE rcvd: 48
I than ran one on a web site that was working (my blog) and here are the results:
frank-villasenors-macbook:mozilla-central-working FrankV$ dig www.theopensourceu.com ; <<>> DiG 9.6.0-APPLE-P2 <<>> www.theopensourceu.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37084 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;www.theopensourceu.com. IN A ;; ANSWER SECTION: www.theopensourceu.com. 3600 IN CNAME theopensourceu.com. theopensourceu.com. 3148 IN A 126.96.36.199 ;; Query time: 98 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Tue Oct 27 18:33:40 2009 ;; MSG SIZE rcvd: 70
They look similar; I don't think this is telling me anything (right now)... Just before submitting this, I refreshed my Ubuntu.com window and the site came up... Perhaps the
dig fixed it?
Update (11/17/2009): I'm still having trouble with this here and there. One additional thing I've noticed is that sometimes the DNS lookups simply take longer than I would expect. For example, if I attempt to go to Superuser.com the web browser (I generally use FireFox) will show the loading screen for 30 to 45 seconds. It could be longer and it could be shorter but at that point sometimes the site eventually loads and sometimes I receive the aforementioned error message.
In case there is question, I have a broadband internet connection (by Comcast in Chicagoland) which generally reports speeds of around 5mbps. Again, I only see this issue on the MacBook. I also have two Vista based computers and a Ubuntu based computer which do not present this problem.