Accelerate your website by configuring a CNAME - Edge Security Acceleration

After you add a domain name, DCDN assigns you a CNAME. You must then point the DNS record for your domain name to the assigned CNAME at your DNS provider. This forwards access requests to DCDN nodes to enable website acceleration, edge computing, and security protection.

Background

Acceleration mechanism

After you add a domain name, the system assigns you a CNAME. This record points to globally distributed DCDN nodes. User requests are routed to these nodes. If a node has the requested content in its cache, the content is returned directly. If the content is not cached, the node requests the content from the origin server and caches it for future access. In this way, DCDN improves content delivery speed and user experience. Make sure that your DNS record points to the CNAME record value provided by DCDN to ensure that traffic is routed through the acceleration service.

Domain name resolution

Domain name resolution is a service that resolves a domain name, such as example.aliyundoc.com, to the IP address that a client connects to. For more information, see What is domain name resolution?

Prerequisites

A domain name is added. For more information, see Add a domain name.

Step 1: Obtain the CNAME for the domain name

Go to the Domain Names page in the DCDN console. Copy the CNAME record value for the domain name.

Step 2: Configure CNAME resolution

The method for configuring CNAME resolution varies based on your DNS provider. Follow the procedure that applies to your provider.

If your DNS provider is Alibaba Cloud, see Alibaba Cloud CNAME configuration.
If your DNS provider is Tencent Cloud, see Tencent Cloud CNAME configuration procedure.

Important

Domain name resolution rules from the same DNS provider may conflict with each other.
Alibaba Cloud DCDN uses servers in the Chinese mainland to verify DNS records. If you configure different DNS records for different regions, a conflict may occur. For example, you might configure the Alibaba Cloud DCDN CNAME only for regions outside the Chinese mainland, such as Hong Kong (China), Macao (China), and Taiwan (China). In this case, the verification servers cannot resolve the CNAME. The CNAME status of the domain name is then displayed as Pending Configuration in the DCDN console. However, this does not affect the DCDN acceleration service.
The CNAMEs for Alibaba Cloud CDN, DCDN, ApsaraVideo Live, and ApsaraVideo VOD can be used only for scheduling and resolution by Alibaba Cloud CDN. Alibaba Cloud reserves the right to disable the domain names and accounts that maliciously use CNAMEs.

Alibaba Cloud CNAME configuration

If your DNS provider is Alibaba Cloud, you can follow these steps to configure the CNAME.

Log on to the Alibaba Cloud DNS console using The Alibaba Cloud Account For The domain name.
Optional: Add the domain name in the Alibaba Cloud DNS console if the domain name is not registered with Alibaba Cloud.
Note
If your domain name is not registered with Alibaba Cloud, you must first add the domain name in the Alibaba Cloud DNS console before you can configure domain name resolution. For more information, see Domain Management. If your domain name is registered with Alibaba Cloud, skip this step.
On the Public Zone page, find the root domain of your domain name and click Settings in the Actions column.

Click Add Record to add a CNAME record.

Note

The CNAME resolution for an exact domain name has a higher priority than that for a wildcard domain name. If your domain name is a wildcard domain name and the host record is set to an asterisk (*), you must delete the DNS records for any second-level domains that have already taken effect under the wildcard domain name.

添加记录

Parameter	Description	Example
Record Type	Select CNAME.	CNAME
Hostname	If the domain name is a root domain, set the host record to `@`. If the domain name is a wildcard domain, set the host record to `*`. If the domain name is a subdomain, set the host record to the subdomain prefix.	Root domain example domain name: aliyundoc.com. Host record: `@`. domain name: aliyundoc.com.cn. Host record: `@`. Wildcard domain example domain name: .aliyundoc.com. Host record: ``. domain name: .aliyundoc.com.cn. Host record: ``. domain name: .example.aliyundoc.com. Host record: `.example`. domain name: .example.aliyundoc.com.cn. Host record: `.example`. Subdomain example domain name: example.aliyundoc.com. Host record: `example`. domain name: example.aliyundoc.com.cn. Host record: `example`. domain name: www.example.aliyundoc.com. Host record: `www.example`. domain name: www.example.aliyundoc.com.cn. Host record: `www.example`. Note The ".com.cn" suffix is an example of a top-level domain that has two parts.
Query Source	Default.	We recommend that you use the default value.
Record Value	Enter the CNAME record value of the domain name. Note Each domain name has a unique CNAME value. A second-level domain cannot use the CNAME of its primary domain name. To accelerate a second-level domain, add it to DCDN and map it to its own CNAME. Alternatively, add a wildcard domain to DCDN. The CNAME of the wildcard domain can be used by its second-level domains. For more information about how to add a wildcard or second-level domain name, see Add a domain name.	www.example.com.w.kunlunsl.com
TTL	TTL is the cache time. The smaller the value, the faster the modified record takes effect worldwide. The default value is 10 minutes.	We recommend that you use the default value.

Click Confirm to add the record.

Tencent Cloud CNAME configuration procedure

If your DNS provider is Tencent Cloud, you can follow these steps to configure the CNAME.

Log on to the DNSPod console.

On the domain name's resolution page, click Add Record to add a CNAME record.

Parameter	Description	Example
Host Record	If the domain name is a root domain, set the host record to `@`. If the domain name is a wildcard domain, set the host record to `*`. If the domain name is a subdomain, set the host record to the subdomain prefix.	Root domain example domain name: aliyundoc.com. Host record: `@`. domain name: aliyundoc.com.cn. Host record: `@`. Wildcard domain example domain name: .aliyundoc.com. Host record: ``. domain name: .aliyundoc.com.cn. Host record: ``. domain name: .example.aliyundoc.com. Host record: `.example`. domain name: .example.aliyundoc.com.cn. Host record: `.example`. Subdomain example domain name: example.aliyundoc.com. Host record: `example`. domain name: example.aliyundoc.com.cn. Host record: `example`. domain name: www.example.aliyundoc.com. Host record: `www.example`. domain name: www.example.aliyundoc.com.cn. Host record: `www.example`. Note The ".com.cn" suffix is an example of a top-level domain that has two parts.
Record Type	Select CNAME.	CNAME
Line Type	Select the Default type.	We recommend that you use the default value.
Record Value	Enter the CNAME record value of the domain name. Note Each domain name has a unique CNAME value. A second-level domain cannot use the CNAME of its primary domain name. To accelerate a second-level domain, add it to DCDN and map it to its own CNAME. Alternatively, add a wildcard domain to DCDN. The CNAME of the wildcard domain can be used by its second-level domains. For more information about how to add a wildcard or second-level domain name, see Add a domain name.	www.example.com.w.kunlunsl.com
Weight	Leave this parameter empty.	Not applicable
MX	Leave this parameter empty.	Not applicable
TTL	TTL is the cache time. The smaller the value, the faster the modified record takes effect worldwide.	We recommend that you use the default value.

Click Save to add the record.

Step 3: Verify the CNAME configuration

Method 1: One-click verification
1. Go to the Domain Names page in the DCDN console.
2. Select the destination domain name. Move the pointer over the CNAME Status of the domain name. If the status is Configured, the CNAME configuration has taken effect.
Method 2: Verify using the nslookup command
1. Open a terminal or command prompt.
2. Enter nslookup -type=CNAME service domain name. If the resolution result is consistent with the CNAME of the service domain name in the DCDN console, the DCDN service has taken effect. Example:
```
nslookup -type=CNAME www.example.com
```

References

If the cache hit ratio is low after you enable DCDN, you can use the prefetch feature to prefetch popular resources before peak hours. This can improve the cache hit ratio. For more information, see Purge and prefetch resources.