Last week I got nailed on my regular workstation. It could not authenticate. I noticed it as as a POP3 problem I thought was related to Scanmail. Then my Firewall client started showing the infamous red X. I switched gears and accelerated the provisioning of my laptop so I could run payroll.
I cannot say that I have fixed the problem but I have fixed a couple of problems along the way and restored network access. I ran netdiag and dcdiag. Finding netdiag was the hardest part. It is located in the Cabinet file but is not installed by default. You need to manually extract it. The diagnostics did not tell me anything so far. DNS and DHCP seem to be okay.
My certificate autoenrollment failed on February 11 so I requested and installed a new certificate.
I do not know how it happened yet by I have network access to the server back. Http is working, too. POP3 still has problems. Oh, well!;)