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I have an ISA 2006 server that out of no where fails on a newly created DNS entry for a website with out any errors being reported on the server side. &nbsp;The website does have a web rule in place that works with out a hitch until it just doesn't work. &nbsp;The DNS client can be restarted on that server which temporarily fixes the issue from a few hours to days.<br />
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The only error message that has been any help is this one. &nbsp;Which is displayed from the users side when it fails.<br />
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Technical Information (for support personnel)<br />
&quot;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Error Code 11001: Host not found<br />
&quot;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Background: This error indicates that the gateway or proxy server could not find the IP address of an upstream (Web) server. This is usually due to a DNS-related error.<br />
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I have an ISA 2006 server that out of no where fails on a newly created DNS entry for a website with out any errors being reported on the server side.  The website does have a web rule in place that works with out a hitch until it just doesn't work.  The DNS client can be restarted on that server which temporarily fixes the issue from a few hours to days.

The only error message that has been any help is this one.  Which is displayed from the users side when it fails.

Technical Information (for support personnel)
"	Error Code 11001: Host not found
"	Background: This error indicates that the gateway or proxy server could not find the IP address of an upstream (Web) server. This is usually due to a DNS-related error.




ISA 2006 Starts denying a DNS entry

Software firewalls, also known as host-based firewalls, provide a layer of software on one host that controls network traffic in and out of that single machine. Most operating systems now include firewall software, but many available software firewalls include central distribution, antivirus systems and disaster recovery.

Software Firewalls

Microsoft Forefront, formerly known as Internet Security and Acceleration Server (ISA Server), is a network router, firewall, antivirus program, VPN server and web cache that runs on Windows servers. It includes identity management and protection systems, and discontinued systems for threat management and network protection, along with protection for Sharepoint and Exchange. The scope of discussions includes forward and reverse proxy, application and service publishing, virtual private networks (VPNs), outbound access rules, SSL certificates and network routing within either a single node or an highly-available array pairing.