Technical Tip: CNAME alias target domain behavior

[cwan]

Description

This article describes the expected behavior for CNAME target reference.

Solution

Available option

CNAME Record

Alias - An alias name to another true or canonical domain name (the target). For instance, www.example.com is an alias for example.com.

Target – The true or canonical domain name. For instance, example.com.

Explanation

Primary domain may reference to an external third party domain (cloud services) for application redirection.

Configuration

# config global-dns-server zone
# edit "www"
#    set domain-name example.com.
#    config  cname-record
#      edit 1
#        set alias app.example.com
#        set target cloud.fortinet.com.
#      next
#    end

Validation

Verify DNS query with the below tools:

• NSLOOKUP
• DIG

Note that the primary domain will append to the configured target domain if trailing dots are not configured

For example: cloud.fortinet.com. example.com

If the target domain expected to be the FQDN, then the trailing dots should be added.

#    config  cname-record
#      edit 1
#        set alias app.example.com
#        set target cloud.fortinet.com[.]   --->  trailing dot (without the square bracket)
#      next