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TR7Enterprise Application Delivery & Security Platform
What is an Express Profile; how does it relate to zone transfer?
Short answer
Express Profile is a reusable definition used to pull a zone on an existing DNS server into GTM with zone transfer (AXFR): the Master Addresses from which the records are taken and the optional record name pattern IDENTIFIER PATTERN. When the profile is selected as EXPRESS in a data center group of a domain, TR7 pulls the zone from the master when the master server sends a NOTIFY or with Sync via Express, and rewrites the group's records according to the zone on the master; the management of the records stays on the master. Zone transfer itself is the standard DNS method; Express uses it for continuous synchronization, while the Zone Transfer button on the record tab makes a one-time transfer with the same method without a profile being defined.
How Does It Work?
- The profile is bound by marking the EXPRESS box of a data center group in the domain form and selecting the profile.
- The master server makes a change in the zone and sends a NOTIFY to TR7, or Sync via Express is clicked on the record tab.
- The servers in the Master Addresses list are tried in order and the first successful transfer is taken (a transfer that starts with a NOTIFY is made from the master that sent the notification). If there is an IDENTIFIER PATTERN, the record names are filtered and converted with it.
- The group's records are rewritten according to the zone on the master; the result and the record changes are seen in the Express Logs window.
There is no refresh on a timer; if the master does not send a NOTIFY, the refresh is done only with Sync via Express.
Comparison
| Express profile | Zone transfer button | Slave Server IPs | |
|---|---|---|---|
| Direction | From the master server to TR7 | From a server to TR7 | From TR7 to secondary servers |
| When | At every NOTIFY and with Sync via Express | Once, when clicked | When the secondary server requests it; TR7 sends a NOTIFY at every change |
| Records | Overwritten at every transfer; all record types are taken | Selected with Collision Decision (Keep Current Records by default, Overwrite, Combine Records) and Record Types to Retrieve | The zone on TR7 is transferred as it is |
| In which group | An Express group | Only a Local group | Domain-wide |
In TR7
- Profiles are defined on the Configuration Menu → GTM → Express Profiles (DNS Integration) screen; a profile has at most 10 master addresses, and a profile can be used in more than one domain.
- Two settings are required on the master server: the zone transfer request coming from TR7 must be allowed, and on changes a NOTIFY must be sent to one of the Frontend IP addresses of the DNS Service. TR7 sends the transfer request from the DNS Service's Frontend IP that is in the same subnet as the master, and if there is no such address, from the first cluster VIP among the service's Frontend IPs.
- In a cluster, only the primary device performs the transfer (if the primary device cannot be reached for longer than one hour, the other device takes over); a transfer triggered on the other device is rejected with the
is not master of GTMerror (How does GTM behave in a cluster?).
Common Misconceptions
- "TR7 checks the master at regular intervals." A transfer starts only with a NOTIFY or with Sync via Express.
- "Changes made on TR7 to Express records are preserved." Every transfer rewrites the group's records according to the master.
- "If the profile is deleted, the records are deleted as well." The groups that use the profile return to Local Management; the pulled records stay in place but are no longer refreshed.
How it is done in the documentation
