The following options in the Start Of Authority (SOA) tab, shown in Figure 5.12, control the contents of the SOA record for this zone.
FIGURE 5.12 The Start Of Authority (SOA) tab of the zone Properties dialog box

■ The Serial Number field indicates which version of the SOA record the server currently holds. Every time you change another field, you should increment the serial number so that other servers will notice the change and get a copy of the updated record.
■ The Primary Server and Responsible Person fields indicate the location of the primary name server for this zone and the email address of the administrator responsible for the maintenance of this zone, respectively. The standard username for this is hostmaster.
■ The Refresh Interval field controls how often any secondary zones of this zone must contact the primary zone server and get any changes that have been posted since the last update.
■ The Retry Interval field controls how long secondary servers will wait after a zone transfer fails before they try again. They’ll keep trying at the interval you specify (which should be shorter than the refresh interval) until they eventually succeed in transferring zone data.
■ The Expires After field tells the secondary servers when to throw away zone data. The default of 1 day (24 hours) means that a secondary server that hasn’t gotten an update in 24 hours will delete its local copy of the zone data.
■ The Minimum (Default) TTL field sets the default TTL for all RRs created in the zone.
You can assign specific TTLs to individual records if you want.
■ The TTL For This Record field controls the TTL for the SOA record itself.
Name Servers Tab
The name server (NS) record for a zone indicates which name servers are authoritative for the zone. That normally means the zone primary server and any secondary servers you’ve configured for the zone. (Remember, secondary servers are authoritative read- only copies of the zone.) You edit the NS record for a zone using the Name Servers tab (see Figure 5.13). The tab shows you which servers are currently listed, and you use the Add, Edit, and Remove buttons to specify which name servers you want included in the zone’s NS record.
FIGURE 5.13 The Name Servers tab of the zone Properties dialog box

WINS Tab
The WINS tab allows you to control whether this zone uses WINS forward lookups or not. These lookups pass on queries that DNS can’t resolve to WINS for action. This is a useful setup if you’re still using WINS on your network. You must explicitly turn this option on with the Use WINS Forward Lookup check box in the WINS tab for a particular zone.
Zone Transfers Tab
Zone transfers are necessary and useful because they’re the mechanism used to propagate zone data between primary and secondary servers. For primary servers (whether AD Integrated or not), you can specify whether your servers will allow zone transfers and, if so, to whom.
You can use the following controls on the Zone Transfers tab to configure these settings per zone:
■ The Allow Zone Transfers option controls whether the server answers zone transfer requests for this zone at all— when it’s not selected, no zone data is transferred. The Allow Zone Transfers selections are as follows:
■ To Any Server allows any server anywhere on the Internet to request a copy of your zone data.
■ Only To Servers Listed On The Name Servers Tab (the default) limits transfers to servers you specify. This is a more secure setting than To Any Server because it limits transfers to other servers for the same zone.
■ Only To The Following Servers allows you to specify exactly which servers are allowed to request zone transfers. This list can be larger or smaller than the list specified on the Name Servers tab.
■ The Notify button is for setting up automatic notification triggers that are sent to secondary servers for this zone. Those triggers signal the secondary servers that changes have occurred on the primary server so that the secondary servers can request updates sooner than their normally scheduled interval. The options in the Notify dialog box are similar to those in the Zone Transfers tab. You can enable automatic notification and then choose either Servers Listed On The Name Servers Tab or The Following Servers.
Leave a Reply