Overview of IPv6 DNS
Each host on the IPv6 network is identified by an IPv6 address. To access a host, a user must obtain the host IPv6 address first. It is difficult for users to remember IPv6 addresses of hosts. Therefore, host names in the format of strings are designed. In this way, users can use the simple and meaningful domain names instead of the complicated IPv6 addresses to access hosts by resolution of the DNS server on the network.
The device can function as an IPv6 DNS client.
As shown in Figure 1, the switch functions as an IPv6 DNS client and supports static and dynamic domain name resolution.
- Static domain name resolution: Mappings between domain names and IPv6 addresses are configured manually. To obtain the IPv6 address by resolving a domain name, the DNS client searches the static domain name resolution table for the specified domain name.
- Dynamic domain name resolution: Dynamic domain name resolution is implemented by a DNS server. The DNS server receives domain name resolution requests from DNS clients. The DNS server searches for the corresponding IPv6 address of the domain name in its DNS database. If no matching entry is found, it sends a query message to a higher-level DNS server. This process continues until the DNS server finds the corresponding IPv6 address or detects that the corresponding IPv6 address of the domain name does not exist. Then the DNS server returns a result to the DNS client.The IPv6 domain name resolution system of the switch must support the following DNS query modes:
- AAAA query: uses a domain name to query an IPv6 address.
- IPv6 PTR query: uses an IPv6 address to query a domain name.