Applies To:
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BIG-IP GTM
- 11.5.10, 11.5.9, 11.5.8, 11.5.7, 11.5.6, 11.5.5, 11.5.4, 11.5.3, 11.5.2, 11.5.1
Overview: Replacing a DNS server with BIG-IP GTM
![Traffic flow when BIG-IP GTM replaces DNS server](/kb/global/manual_images/MAN-0388-04_v1/i_gtm_replacing_dns_server.png)
About listeners
A listener is a specialized virtual server that passively checks for DNS packets on port 53 and the IP address you assign to the listener. When a DNS query is sent to the IP address of the listener, BIG-IP GTM either handles the request locally or forwards the request to the appropriate resource.
Task summary
Perform these tasks to replace a DNS server with BIG-IP GTM.
Configuring BIND servers to allow zone transfers
When you want to improve the speed of responses to DNS queries you can configure a BIND server to allow zone transfers only to the DNS Express engine on the BIG-IP system. You do this by adding an allow-transfer statement to named.conf on the BIND server.