Solved

Website error

Posted on 2014-02-03
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Last Modified: 2014-04-05
Very occasionally and randomly (last happened yesterday, then the time prior ~3 weeks earlier, and then it was a couple of days before that)

Whilst trying to access the company's website (which is hosted offsite), we will be unable to access the site with just the word "Error" in the top left corner of the page.
-Can telnet to the site's IP address no problem
-Can ping the sites DNS name ok
However this is isolated only to this site, if we connect to the website from a mobile device connected to 3G or connect from another computer offsite the website can be accessed no problem.
This will only remain for about 5 minutes before everything starts working normally again.

This office has a student lab with about 20PCs (which on the last incident none were being used and most were not even turned on) and my concern is that there could be some sort of attempted security breach on the network.

I don't know if this is way off track, but I was wondering what could be the next step to isolate this down further?
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Question by:progressit
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9 Comments
 
LVL 7

Expert Comment

by:Milind Koyande
ID: 39829266
Hello Progressit,

Is it possible to provide Website name or Screenshot of the website (with error). Also please let us know the webserver details (if you have).
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Author Comment

by:progressit
ID: 39831243
Website is http://www.ltt.com.au

And all I know about the webserver is that it's cPanel
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LVL 7

Expert Comment

by:Milind Koyande
ID: 39831614
Right now I am unable to see any Error on top left corner of the page but When you see the error next time you can take screenshot and share here.

Also if your website hosted on a dedicated or VPS server (you own it) then you can check the error log using command:
tail -f /usr/local/apache/logs/error_log

Open in new window

Or you can contact your webhosting provider and ask them to check the logs.
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LVL 27

Expert Comment

by:skullnobrains
ID: 39835280
looks like a local proxy at your location is malfunctionning.

please confirm the following :
- are you able to browse other sites from that same location properly while you have the error on this one
- are you able to access that same site at the same time though a 3G or other network
- do you have the same problem with other machines at the same location and at the same time ? or at different random times ?
- can you try a different browser ? do you have the exact same error ? does it display identically ? which browsers did you use ?

http errors can be made accidentally persistent if you have a proxy. likewise dns queries (including errors) are cached at different level including by the browser itself, the os, most likely a dns proxy at your location, possibly an ISP proxy...

other than the above, first thing would be to determine what sends the weird "error" message

my current guess would be cpanel sometimes displays this weird error page instead of your site, and your local proxy caches the answer for 5 minutes. from non-proxied sites, you'd likely just refresh the page and hardly notice the error.
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Author Comment

by:progressit
ID: 39849005
-We CAN browse other sites from that same location whilst the error is occuring
-Yes we CAN access the site at the same time through 3G or other network
-All machines at the same location cannot access the site at the same time whilst the error is occuring
-Different browsers make no difference, still cannot access site for ~5mins, not sure if the 'Error' message occurs on all browsers or just IE, will have to wait for next occurrence to check

We don't use any proxy servers, however we do use DNS forwarders to our ISP instead of root hints.

Our router performs IPS and A/V scanning, however I've previously turned these off and the issue still occurred.
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Expert Comment

by:skullnobrains
ID: 39932478
sorry i did not see your answer before (too much mail in my box)

you still may have a transparent proxy set by your isp but it is unlikely

- check that the DNS gives the proper IP
- i'd assume the "error" stuff means the connection was rejected (if it occurs quickly and not after a timeout)

can you either provide a trace or run a complete telnet test ?
connect to the ip or name
send "GET / HTTP/1.1"
send "HOST name.of.site"
send ""

i'm interested in
- any icmp packet that terminates the connection (something like network-unreachable, for example. if so run 2 traceroutes when it works and when it does not )
- an actual "error" http page transmitted which would indicate a proxy or possibly a server misconfiguration. the exact source would be welcome
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Accepted Solution

by:
progressit earned 0 total points
ID: 39968407
This hasn't happened again for so long so unable to keep troubleshooting. Hopefully will stay good :\
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Author Closing Comment

by:progressit
ID: 39979828
Previous issue hasn't reoccurred and is all working.
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