ADC

Create CNAME records for a subdomain

A canonical name record (CNAME record) is an alias for a DNS name. These records are useful when multiple services query the DNS server. The host that has an address (A) record cannot have a CNAME record.

Sometimes, a Citrix ADC appliance in proxy mode requests an address record from the cache instead of the server.

Add a CNAME record by using the CLI

At the command prompt, type the following commands to create a CNAME record and verify the configuration:

- add dns cnameRec   [-TTL ] - show dns cnameRec  

Example:

> add dns cnameRec www.example.com www.examplenw.com Done > show dns cnameRec www.example.com Alias Name Canonical Name TTL 1) www.example.com www.examplenw.com 5 secs Done 

To remove a CNAME record for a given domain, type therm dns cnameReccommand and the alias of the domain name.

Add a CNAME record by using the GUI

Navigate toTraffic Management > DNS > Records > Canonical Recordsand create a CNAME record.

Cache CNAME records

When deployed in a proxy mode, the ADC appliance does not always send the query for an address record to the back-end server. This behavior occurs when for an answer to a query for an address record, a partial CNAME chain is present in the cache. There are few conditions in which the ADC caches the partial CNAME record and serves the query from the cache. Following are the conditions:

  • Citrix ADC must be deployed in a proxy mode.
  • The response from the back-end server must have a CNAME chain, for which the record type of the last entry in the answer section must be a CNAME and the question type not a CNAME.
  • The response from the back-end server cannot be a No-data or NX-Domain.
  • The response from the back-end server has to be an authoritative response.
Create CNAME records for a subdomain