Beginning at 11:59pm on July 18, 2004, our NOC engineering will begin upgrading the IOS code on all of our Cisco 3750 Layer-3 switches. These upgrades are necessary to correct a critical flaw in the existing code that they are running. Engineers will upgrade one switch at a time, making sure that the current
one returns to normal service before moving on to the next one. The total time for each switch to be upgraded and reloaded will be about 10 minutes (barring any unforeseen issues). During the reload, the server will be unavailable. The new code has been running on production switches for several weeks without issue, so we don't anticipate any problems with the upgrade.

We want to stress that while the maintenance window is 3 hours total, the anticipated downtime for the server is only about 10 minutes.

If you have any questions or concerns, please contact us.

I know the subject line says the affected server is windows2, but is this having an effect on anything else, because all my sites are down at the moment. (server21).

Nope, we're just doing some technical actions at the server21 at the moment.
It will be online in about 10-15 minutes.