I had a problem in my home lab for some times (about several days) but I didn’t find times to look over it.
I planned some clean up to do for tonight, this one was one of them; I’ve two physical hosts which I added them to the vCenter; for some reason they disconnected automatically and when I added them back, that happened again.
I tried to add host to the vCenter two times and take their available time, it’s about two minutes.
I searched for “VMware vCenter ESXi 4.1 disconnect reconnect connection 2 minutes” in the google and found this thread in the VMTN (VMware Community).
The problem in that thread was some security appliance but I don’t have one and as far as I remember I turned off the firewall on vCenter Server System.
I checked the firewall and … YES …
It was there, it seems after some work I did on that system the firewall state changed for some reasons, so it blocked 902 UDP port and the result was that, so I turned off the firewall.
Just after turning off the firewall, everything changed back to the normal state automatically.
So, Next time I face some problem like this, I’ll check firewall before doing the rest of works. 😉