DNS on Windows 2000, Second Edition

Coping with Disaster

When disaster strikes, it really helps to know what to do. Knowing to duck under a sturdy table or desk during an earthquake can save you from being pinned under a toppling monitor. Knowing how to turn off your gas can save your house from conflagration.

Likewise, knowing what to do in a network disaster (or even just a minor mishap) can help you keep your network running.

Long Outages (Days)

If you lose network connectivity for a long time, your name servers may have problems. If they lose connectivity to the root name servers for an extended period, they’ll stop resolving queries outside their authoritative zone data. If the slaves can’t reach their master, sooner or later they’ll expire the zone.

In case your name service really goes haywire because of the connectivity loss, it’s a good idea to keep a sitewide or workgroup HOSTS file around, as we recommended earlier in this chapter. If your name servers all go down, your hosts will still be able to resolve the names of hosts in the HOSTS file.

As for slaves, you can reconfigure a slave that can’t reach its master to run temporarily as a primary master. Just right-click on the zone’s domain name in the DNS console, select Properties, make sure the General tab is selected, and click on Change... to change the zone type from secondary to primary. If more than one slave for the same zone is cut off, you can configure one as a primary master temporarily and reconfigure the other to load from the temporary primary. ...