Firmware update stopped connection to server

I hate when you think you have fixed a machine but realise that you have created a seperate major problem.
I had a Konica Bizhub C308 that was reportedly skewing and blurring scans.Skewing scans is a common problem and easily fixed by realigning the Document Feeder. While I was doing that I had a quick look at the firmware and saw that it was running version G00-54. That is really old and probably explains the blurred scans. G00-54 was notorious for scan quality problems so I loaded the latest firmware I had which is GC2-R9. No more scanning issues.

So I am about to leave, feeling good about a job well done, when the secretary says "Um, I can't print".

So I am wondering how updating firmware now prevents printing. I hopped on a computer and had a look at the print queue and see that it is on a remote server, is full of jobs and is reporting that the printer is in error. As a quick test I installed a new printer on the local computer and am able to print ok. Next step is to call the IT support for the remote server and let them look at the server. After they do the same tests as me they determine that it is a server side issue and they will fix it. I am still highly suspicious of the firmware update. So I call around the other techs to see if they have had this issue. The finale guy I called remembered an E-mail from a couple of years ago alerting to a problem with an old firmware. Auto Selective IP Address Filtering is turned on by default. 

So while the IT guys are messing around I have a look at the IP settings and see that the IP filtering has been turned on. This means that the machine is filtering out traffic from the remote server but still accepting traffic from the local network. I turned the setting off and the machine starts printing.

I let the IT guys take the credit for fixing the problem rather than admitting that I had caused it.