LAN Clients being blocked from one site only
Posted on 2015-01-07
We have one particular website that our client computers that are inside our network are now being blocked from(Which is to say that they just won't load - No error codes). The site has always loaded but suddenly stopped. This site can be accessed via other networks outside of our LAN with no issue. It's just one site but it's a webhosting site so we cannot login from the office to manage our websites so it's important to us. There were no changes on any server or firewall. We can get to all other websites but this one.
DNS Server: Small Business Server 2008 - This is the only DNS server and is the only computer that can still access the site in question
-Checked DNS Config - using forwarders to the ISP DNS servers. It's been working for over 5 years
-Cleared DNS Cache
-Restarted DNS Service
-Ran the "fix my network" wizard from the SBS console but it didn't find anything to fix
Clients: Windows 7 Pro and MAC OSX
-Configured properly to the local DNS Server via DHCP or Manually configured IP but no go
-DHCP working properly
-Checked Windows firewall - configured for DNS
-Opened a ticket and they checked their end out and it was clear
-Unplugged our firewall appliance from the ISP equipment and replaced it with just a laptop configured with the ISP addressing and the site worked.
Gateway(Firewall Appliance Sonicwall NSA)
-Verified that the DNS server itself which has the same addressing as the clients can access the site and it does.
-Checked logs - no indication of the site being blocked. These servers are in the USA and we don't content filter anything from the USA but went ahead and made this site a safe site but still no go.
-Went ahead and made a rule to allow traffic to this domains address but still no go
: It seems to be an issue with the DNS server service itself but I cannot find anything wrong. The clients can get to all other websites but only the DNS server itself can get to this one website(netjelly.com)
Any insight would be appreciated.