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Title
Laptop Workstation switching back and forth between two IP Address of WiFi and LAN blocked or IP address is not reachable -
Description
Erorr messages found in the Activity Center:
Access to the resource was denied
Information RPC ports are blocked or IP address is not reachable
System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
Hercules.Modules.Exceptions.RpcServerUnavailableException: Access to the resource was denied
Warning Caught a COMException: "(0X8007203A) The server is not operational."
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Cause
This issue was found when the workstation's IP address is set as the network address. Performed a local /ipconfig on windows workstation to determine the IP Address. But when performing a nslookup from the workstation it shows a different IP address.. -
Resolution
It seems that this would be related to DNS cache. Since Safeguard is associating a DNS name with a particular IP address, that the Laptop system is switching back and forth between IPs. So it is only successful when it's using the address that Safeguard thinks is correct. Unfortunately, there is no way to flush the DNS cache in Safeguard.A possible solution is to try to alter the TTL (Time To Live) values for DNS records to cause Safeguard, and DNS resolvers, to refresh cached DNS records more frequently? A lower TTL would force Safeguard to query DNS when the TTL runs out.What is the current TTL for DNS set to?https://support.rackspace.com/how-to/about-ttl-best-practices/Safeguard depends on DNS. If the Host names ip address changes then the only way that Safeguard would get a new resolved IP address is if reduce the Time to Live of the DNS cache which would force SG to lookup against DNS for the IP.