Fellow IT guy here (welcome!). It's like everyone else said: have some proof that your boss was informed of the situation. As someone who worked for a few years in IT: avoid verbal agreements; you won't be able to prove they happened and they'll make it your fault. As an example, I refuse to do any work that might have long-term consequences if I don't have a ticket requesting as such or at the very least a mail in my mailbox. All agreements should be documented somewhere. Email is good, hard copies (paper) are even better.

Always, always, always document your requests. Bosses will not hesitate to throw you under the bus when something THEY fucked up goes wrong. Like southsamurai said: cover your ass, then follow orders. When shit inevitably hits the fan, you'll have something to point to.