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Weird 'DNS' problem

Posted on 2010-09-22
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Last Modified: 2013-12-08
I've got a strange problem.  I have a site where the clients are unable to access www.flickr.com (they use it for research).  The site resolves so DNS appears to be working fine but if I type the address in IE, FF, Safari, etc - the site fails to load.  'Cannot display page' is the generic error among all browsers.  If I put in the resolved IP address - it works fine.  

Any thoughts?
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Question by:GDavis193
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Expert Comment

by:chapmanjw
ID: 33738290
Do you have a proxy server or other web filtering server/software?
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Author Comment

by:GDavis193
ID: 33738324
No proxy.  All cleints go straight out.  There is a Sonicwall in place but even if I add flickr.com to a trusted domain - the symptoms remain the same.

It acts like it can't resolve the name - its the same browser error y ou get when DNS fails.  But it resolves.

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Accepted Solution

by:
chapmanjw earned 400 total points
ID: 33738398
Does it happen to all the PC's or just one?

What are you using for a router?  Is it a router like you would use at home or is a server acting as the router to get to outside traffic?
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Assisted Solution

by:MarkusId
MarkusId earned 25 total points
ID: 33738442
Hi,

Which operating system are the clients running on? If it is Windows, what is the output of the dos-command

nslookup www.flickr.com

Does it show the correct IP address?

Best wishes,

Markus
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Author Comment

by:GDavis193
ID: 33738483
Yes, it's the IP address I'm plugging into the browser to get to the website.  DNS resolves flickr.com but if I put flickr.com into a browser - it doesn't display the page.  if I put the IP, it works fine.
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Author Comment

by:GDavis193
ID: 33738492
It does it from all workstations / servers / macs.  I've used multiple browsers.  We are using a Sonicwall and I've added flickr.com to trusted domains.  

It's weird...
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Expert Comment

by:chapmanjw
ID: 33738555
Since you are using Sonicwall, I would give their tech support a call.  There may be an aspect of it's filtering that hasn't been looked at.
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Assisted Solution

by:Hypercat (Deb)
Hypercat (Deb) earned 25 total points
ID: 33738917
I would try clearing your DNS cache on the server for the flickr.com domain and see if that helps.
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Assisted Solution

by:Sudeep Sharma
Sudeep Sharma earned 25 total points
ID: 33739315
what do you get if you do telnet to www.flickr.com on port 80?

telnet www.filckr.com 80

what's the output of the command?

Sudeep
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Assisted Solution

by:digitap
digitap earned 25 total points
ID: 33739551
Try this...open Internet Explorer and login to the sonicwall website.  From the same workstation, open another IE browser Window and go to Flickr.  What happens?
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Author Comment

by:GDavis193
ID: 33739681
@hypercat: I tried ipconfig /flushdns - no go

@SSharma: if I telnet to www.flickr.com 80 then it looks like it hangs.  I hit enter a few times and the cursor drops.  if I hit CTR+C then Enter, I get what looks like HTML code that scrolls across the page.

@digitap: I logged into the Sonicwall Admin Console then went to flickr using another instance of IE - does not work.

I would say it's an IE thing but I've tried this from an XP workstation and a MAC using 3 different browsers with the same result.  Unable to display page.

Waiting for a callback from Sonicwall....

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Expert Comment

by:digitap
ID: 33739876
the workstation logged onto the administrator console of the sonicwall bypasses the sonicwall "security" features...by default.  so, it's an easy way to determine if the sonicwall is the culprit.  of course, this feature can be disabled, so....
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Author Closing Comment

by:GDavis193
ID: 33747166
thanks
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Author Comment

by:GDavis193
ID: 33747173
Oops, I meant to give credit to the post from Chapman on calling Sonicwall as it was actually a Sonicwall problem.
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Expert Comment

by:digitap
ID: 33747194
You can Request Attention to your question and you will be allowed to reallocate points.
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