Interview Back in late 2010, "Zimmie" was working in IT support for a vendor that made VPN devices and an associated operating system. He got a call on a Monday from a customer – a large specialty retailer in the US – about its VPN hardware that had stopped working over the weekend. After looking into the report, the problem appeared to be the result of a certificate validation failure, as he described in a recent post on Mastodon. "My then-employer's VPN devices are managed by a central server,...