In the last few days our Exchange 2003 server (SP2), running on Windows Server 2003 SP2, has been running very slowly. We've noticed that a process called inetinfo.exe is constantly using 100% or just slightly less than 100% of the CPU's capacity, as well as 500,000k of memory. The process store.exe is similarly running at about 600,000k of memory.
Searching the Internet has turned up lots of suggested causes of this but none seem to apply to us. I've tried disabling our anti-spam software (Sophos PureMessage), our spam filtering software (SurfControl) and a 3rd party application we use called Exclaimer to no avail. We have no backlog of messages in our Exchange queues which would suggest a reverse-NDR attack, and realying is tied down to just four IPs within our network which are rightly permitted to do so. I've also checked that the inetinfo.exe is what it purports to be - it's in C:\Windows\System32\Inetsrv\ which seems to be the legitimate location.
Can anybody suggest anything else to check? I'm out of ideas!