Users often complain about long load times when trying to access IT services (Web, Citrix, Terminal Server ecc.). Also cloud services like Office 365 can be concerned. Increased load times can have various reasons – one of this reasons may be an elevated timespan needed to resolve the DNS address. To discover such problems we have implemented a new DNS plugin in the NetEye Real User Experience (RUE).
Before talking about the new plugin, let’s give a look at the single steps required for the DNS resolution. Please consider the illustration below:
The DNS resolution is the process, which translates a DNS address into an IP address. Once the IP address is obtained, it can be saved within the DNS cache for a certain time. Another request for the same domain can be fulfilled very quickly as long as the IP address remains in the cache. When time to live expires, all steps for the DNS resolution have to be made again.
To monitor this respond times the new DNS plugin collects different information.
Some of them:
Moreover, RUE allows you to graphically represent the collected data to better understand and interpret information collected.
The service plus.google.com has a very low application latency (~5 ms), but the answer from the secondary DNS, which resolves the host plus.google.com comes up with elevated latency (~1.5 sec.). Users will claim low load times, but they can’t neither be assigned to the service nor to the web. They derive from DNS misconfigurations or excessive DNS utilization.