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I have some websites that are not resolving for SOME users using a certain internet provider. Two of the websites are on totally different servers. If people try to get to the websites from their home, using the local internet provider, the website will try for a few minutes and then say the website could not be resolved. It doesn't matter what system they use (mac, pc, linux) or what browser they use. The oddest part is that when they use their cell phone data plan they can get to my websites just fine.

Two of the websites are http://www.cstx.gov and http://click2gov.cstx.gov/Click2GovCX/index.html

It seems very random who can and cannot view the websites. Some people may not be able to view it for a few days and then the issue will resolve for them. Others still can't see the sites after MONTHS....

Wendy W
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  • Have you checked your caching settings? Are you allowing long term, third party (i.e. by the certain internet provider) caching of an old page? – Colt Jun 29 '16 at 14:47
  • IIS has enable cache and enable kernel cache checked, but the other server is not using IIS, so I don't know. – Wendy W Jun 29 '16 at 15:14
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    I am not seeing any _obvious_ caching issue in the response headers for either site, _but_ I do note that both are being pretty aggressive about preventing certain tools from even accessing the sites. You might check to see whether you have used a tool that has _over secured_ the sites and are inadvertently preventing desired traffic. – Colt Jun 29 '16 at 15:33
  • I dont have control over the tools you speak of, could you tell me what ones you know are being blocked. I am trying to convince the network guys that there is something wrong, but I only maintain the websites and don't have access to the tools they use. – Wendy W Jun 29 '16 at 15:40
  • Both of the DNS servers for this domain are within the same network. (within 2 IP addresses of each other) Given the problems that Marko has observed I won't flag this as a duplicate, but please consider reading [Why is geo-redundant DNS necessary for small sites?](http://serverfault.com/q/710108/152073) and the BCP document that it references. – Andrew B Jun 29 '16 at 18:57

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I cannot access either of those two websites from the UK, over broadband or cellular. DNS resolution is fine for both sites, however there is no connection on port 80. Telnet to either IP address gets no SYN/ACK response from the server.

If other people are able to access the site without issue then there is most likely an overly restrictive access control rule somewhere which is breaking things.

Mark Riddell
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  • Thank you MarkoPolo I do know you are not supposed to be able to view it, because there are restrictions for anyone outside of the US to view the site. Not my idea... :( – Wendy W Jun 29 '16 at 17:22
  • I wonder if the users having issues are getting caught up in the region restrictions. – Mark Riddell Jun 29 '16 at 17:31
  • so far it is local people, using our local internet provider that have the issue. I had a few people that were from canada and the network guys added their IP into the allow ip list. – Wendy W Jun 29 '16 at 18:07
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You say that the websites are not resolving. If this really is the case (impossible to say without the actual error messages) then its nothing to do with your server software, it's a DNS problem. Indeed, according to pingdom, "Delegation not found at parent". More specifically, the nameservers for cstx.gov aren't offering any information about www.cstx.gov

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symcbean
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