If you've been watching the series on RPC/HTTP I recorded a little while back, you'll know that I did a "trick" to allow both OWA and RPC/HTTP connectivity through a single external IP Address under ISA Server 2004. There was an annoying flaw which although caused no problem directly, caused ISA Server to log warnings about multiple IP addresses on a single network interface. I'd just lived with this for a long time not worrying about it, but now that I have MOM also running (just) at home, the alerts are getting on my nerves.
Well, I kind of had a busy but not so busy time over the Christmas break. One Virtual Server host machine was rebuilt on new disks as an an additional domain controller running Windows Server 2003 R2 this time. My other VS host now also needs updating to R2, but that will have to wait a couple of weeks. I also went through a full IP renumbering of my home network - primarily because I want to configure VPNs to & from other networks also using the 192.168.0.x range, plus have several easily managed subnets for quarantine, wireless access etc. The other thing I did simultaneously to the renumbering was move my "production" ISA Server into a Virtual Machine. I had a badly configured standby VM running if the physical ISA Server, a struggling and lowly old PIII/700 with 256MB RAM were to finally go bang. However, I built a new clean VM instead.
Back to the plot though. What I never thought of when doing my RPC/HTTP configuration was simply to use a loopback adapter as an additional network in ISA Server to bounce OWA traffic through rather than providing a secondary IP address to an existing network card. Obvious in it's simplicity in retrospect, and means that there's no more annoying ISA Event Log entries.