Powershell: Measuring latency on DNS queries
A little while ago we have some issues with one of our Exchange environments. The symptoms was that basically everything was slow, opening address books, owa, sending mails and so on. After some digging it occurred to me that this may be DNS related, so I used a one-liner in powershell to see how fast our DNS servers responded: Measure-Command {Resolve-DnsName google.com -DnsOnly -Type A -NoHostsFile -server x.x.x.x} And sure enough, we were seeing response times in the range of 5-7 seconds. Way more than enough to cause our problems. After rebooting the DNS servers ours problems disappeared. But, as always, I had to play around with created a powershell function. The function resolves a few records from locally defined DNS servers and some publicly available DNS servers (or a custom list if you want) and measures the average latency (in milliseconds). The results are put in a list and…