Sometimes you are less than careful and a small change leads to being stuck in a not so nice smelling pool of biologicals.
Well, some people have not so good days, some bad days and some worst.
The customer has endpoint security and it checks the internal clients if they are valid and updated anti-virus. (802.1x)
I was doing to OS upgrade for the anti-virus server and the clients were not updated, so they slowly got expired and the endpoint security lock them down. This could be have been easily explained if not for the Primary DNS works which caused the endpoint security to another lockdown when the Primary DNS did not response.
A most less than the desired sequence of events.
Well, I hope this does not turn out as a dear old lady put ” Annus horribilis “.
To restore customer confidence, stick to after-hours work and perform more end to end checks.