Point a subdomain with a CNAME record

Make a subdomain an alias of another hostname with an Edge DNS CNAME record, from Azion Console, the Azion CLI, or the API, and check the answer.

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You can point a subdomain to another host with a CNAME record in Edge DNS from Azion Console, the Azion CLI, or the Azion API. The record below makes blog.example.com an alias of www.example.com, so a query for blog gets the address of www. A CNAME cannot be named @: to point the root domain, refer to Point an apex domain with ANAME instead.

Select an interface. The prerequisites and the procedure below switch with it.

Prerequisites

  • A zone for your domain in Edge DNS. To create one, refer to Create, edit, or delete a zone.
  • The hostname the alias points to. This example uses www.example.com, an A record on www in the same zone that answers 192.0.2.1.
  • The Edit Edge DNS permission. It requires View Edge DNS. Refer to Teams permissions.
  • The Azion CLI installed and authorized.
  • The ID of the zone. azion list dns-zone prints it in the ID column.

Add the CNAME record

The record name is relative to the zone: you enter blog, and Edge DNS serves it as blog.example.com. The value is the one hostname the alias points to. Replace example.com with your domain in every step.

To add the CNAME record with the Azion CLI, replace <zone-id> with the ID of your zone and run:

azion create dns-record --zone-id <zone-id> --name blog --type CNAME --rdata www.example.com --ttl 3600

The command prints the ID of the record:

Created DNS record with ID 100774

The zone holds the alias. Pass blog alone in --name: a name typed with the domain is served with the domain twice.

To add the CNAME record with the Azion API, send a POST request to the zone’s records endpoint. Replace <zone-id> with the id of your zone and [TOKEN VALUE] with your personal token:

Shell
01curl -X POST https://api.azion.com/v4/workspace/dns/zones/<zone-id>/records \
02 -H "Authorization: Token [TOKEN VALUE]" \
03 -H "Content-Type: application/json" \
04 -d '{"name":"blog","type":"CNAME","rdata":["www.example.com"],"ttl":3600}'

A 201 returns the record:

JSON
01{
02 "state": "executed",
03 "data": {
04 "id": 100177,
05 "description": "",
06 "name": "blog",
07 "ttl": 3600,
08 "type": "CNAME",
09 "rdata": ["www.example.com"],
10 "policy": "simple",
11 "weight": 255
12 }
13}

The zone holds the alias. rdata carries the one target hostname, and policy and weight keep their defaults.

To add the CNAME record in Azion Console:

Open the Edge DNS page

Access Azion Console > Edge DNS.

Open the zone

On the Zones page, select the row of the zone.

Select the Records tab
Select + Record

The Create Record drawer opens.

Enter the subdomain

In Name, enter blog. The Console shows your domain after the field and adds it for you.

Select the CNAME type

In Record Type, select CNAME - Canonical name.

Keep the TTL

Keep TTL (seconds) at 3600.

Enter the target hostname

In Value, enter www.example.com.

Select Save

The Console shows Edge DNS Record has been created, and blog appears in the Records table.

Once blog holds the CNAME, it holds no other record type: Edge DNS refuses an MX or CAA record on blog with 19018. For every CNAME rule and its error, refer to Record types.

Check the answer

Ask Azion’s nameserver directly, without your resolver’s cache. This check works before you delegate the domain to Azion.

To query ns1.aziondns.net for the alias, replace example.com with your domain:

dig +short @ns1.aziondns.net blog.example.com A

The nameserver returns the target hostname, then the address of the target:

Text
01www.example.com.
02192.0.2.1

The target is in the same zone, so Edge DNS answers the CNAME and the A record of www in one response. A name that nobody queried before you saved it answers within seconds. A later change to the record can take a few minutes to reach every nameserver. For how answers are cached, refer to How Edge DNS works.

If the command prints nothing, refer to A new record returns NXDOMAIN.

Next steps

Point an apex domain with ANAMEAnswer for the root domain, where a CNAME is refused.Record typesEvery CNAME rule and the error the API returns for each.Add, edit, or delete a recordChange the target of the alias, or delete it.Migrate nameservers to AzionDelegate the domain so public resolvers ask Edge DNS.