IIS & SMTP Services Shutting Down

I have a domain with 15 servers. Any server in that domain with either IIS or SMTP installed will simultaneously stop.

Actually, all IIS services stop and any SMTP service becomes disabled.

I have looked for some rogue Group Policy setting and found nothing. I have scanned and rescanned for viruses and rootkits and found nothing.

I’m showing no unusal activity or traffic between servers or at the firewall. I’m showing no spike in CPU, memory, etc at each individual server level.

For two days in a row the services all stopped early in the morning, waited about 4 hours to do it again but then started stopping every 1 hour or so. In other words, the frequency seems to pick up as the day goes on.

Any ideas would be appreciated.