This morning I noticed that some of our network elements are using IPs that have more than one PTR associated with them. This isn’t a huge problem, but it was exposed to us because the DNS record in our monitoring system would just randomly pick a PTR when the element was rediscovered. Because these other PTRs were often just out of date cruft, having the old names show up in monitoring was confusing. I took this as a quick project to run through the IPs and resolve the duplicates. The fact that I’m now writing a blog post about it is a pretty good spoiler that it wasn’t as simple as I thought it was going to be.
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