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TR7Enterprise Application Delivery & Security Platform
What is the difference between an A record and an AAAA record?
Short answer
An A record maps a name to an IPv4 address (e.g. 203.0.113.10), and an AAAA record maps it to an IPv6 address (e.g. 2001:db8::10) (RFC 1035, RFC 3596); both can be defined together for the same name, and the client selects which one to use according to its own network support. In TR7 GTM, both types are selected from the Record Type list and the address is entered in the Record cell; an address that does not match the type is rejected with the Requires IPv4 or Requires IPv6 warning (record type specific fields). Geographic Proximity in the Balance Algorithm list is effective only on A and AAAA records.
Where It Is Used in TR7
| Where | Field / label | What for |
|---|---|---|
| GTM → GTM Services → service name → Records → Add | Record Type = A / AAAA | Name → IPv4 / IPv6 mapping |
| Same form | Record cell; Requires IPv4 / Requires IPv6 warning | Checking that the address matches the type |
| Same form | Balance Algorithm = Geographic proximity | Returning the address geographically closest to the client (only A and AAAA) |
| Load Balancer → Profiles → Health Checks (DNS) | DNS Record Type = A (default) / AAAA | Checking the DNS server with an A or AAAA query |
| GTM → GTM Services → service name → Dashboard → Query Types | A Queries and AAAA Queries panels | Monitoring the share of A and AAAA queries separately |
Comparison
| A | AAAA | |
|---|---|---|
| Address family | IPv4 (32 bits) | IPv6 (128 bits) |
| Example value | 203.0.113.10 | 2001:db8::10 |
| For the same name | Can be defined together with AAAA | Can be defined together with A |
| Geographic proximity in TR7 GTM | Effective | Effective |
- Multiple addresses can be entered in a record; which of them return in the answer is determined by the HC condition of each address and by the Balance algorithm (Records · The Record Resolution Logic).
- If the record is to point to another name instead of an address value, CNAME is used (What is a CNAME record?).
Common Misconceptions
- "AAAA is the backup of the A record." The two return different address families; the client selects which one to use according to its own network.
- "Only one A record can be written for a name." In TR7 GTM, a record carries multiple addresses; a second record with the same name and type, on the other hand, is blocked with the Record is used warning, and the address is added to the same record.
- "Geographic proximity works on every record type." It is effective only on A and AAAA records; on the other types, it behaves like All records.
How it is done in the documentation
