I created two identical Ubuntu 11.4 32-bit server VMs on the same VMware host (testbox and toolbox). Both installed off the same ISO image and have identical hardware settings. Testbox runs just fine, never had a single issue, but toolbox box becomes inaccessible for 5-10 minutes periodically (once or twice per hour). I can't access it via SSH or http but VMware Remote Console works just fine. I tried hitting web sites from the remote console at such "hangs" and it worked fine too.
I verified the system log files, nothing abnormal there. During the outage testbox works just fine, so it's probably not the VMware server issue either. All boxes on our network are assigned a static IP, so network settings might affect it, but I not sure how to troubleshoot that.
I would greatly appreciate if you can share your experience supporting or at least point out where to start looking.