In this video I wanted to show you an issue that I encounter quite often. DNS is one of those protocols we all take for granted and most people believe that if its working, you can’t do much to tune it.
There are many things you can do to improve DNS performance. One of the more common techniques is to configure a device as a local DNS server, cache or relay for those scenarios where you might have slow internet connections.
I want to focus on the client configuration. I’ve seen DNS server entries (manual or DHCP assigned) that are problematic. For example, DNS servers that no longer exist, typos, slow DNS servers or DNS servers that are located on slow links or paths.In this case I highlighted what your packet trace will look like when you attempt to use a device as a DNS server that is not a DNS server. I also explain why the ICMP packets are important in this process.
Big take away is to review your DNS or any name server configurations every so often to ensure there isn’t any issues.
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