CNAME Configuration

Understand CNAME records

The CNAME record creates an alias for your domain name that points to the Sundun edge server. When a user visits your website, DNS resolution directs them to the nearest Sudun access point.

用户请求 → DNS 查询 → CNAME 解析 → Sudun 边缘节点 → 源服务器

Get your CNAME target

Once you add a domain name in Sudun, you get a unique CNAME target:

1. Go to the WEB Acceleration Domain Name Management page in the control panel to view the CNAME address
2. Select your domain name and go to your domain registrar platform to modify your DNS settings
3. Copy the CNAME address you generated in SuDun (format: )example-com.Sudun.com

Configure the CNAME record

For subdomains (www, api, cdn, etc.)

Add a CNAME record to your DNS provider:

DNS configuration example:

www.example.com. 300 IN CNAME example-com.Sudun.com. api.example.com. 300 IN CNAME example-com.Sudun.com. cdn.example.com. 300 IN CNAME example-com.Sudun.com.

For root/vertex domains

The root domain name (example.com without www) cannot use a standard CNAME record due to DNS RFC restrictions. Please use one of the following alternatives:

Scenario 1: CNAME Flattening (Recommended)

Some DNS providers support CNAME-like functionality at vertex domain names:

Scenario 2: Use Sudun on-site DNS

Migrate your DNS to Sudun for full vertex domain support:

1. Go to the DNS Resolution domain list in the Control Panel
2. Add a domain name here to enable Sudun DNS
3. Update your domain's nameservers to:

- ns1.Sudun.com

- ns2.Sudun.com

Scenario 3: Use the A-record of the anycast IP

Using Sudun's anycast IP address (Enterprise only):

example.com. 300 IN A 198.51.100.1 example.com. 300 IN A 198.51.100.2

Note: Contact support to get the anycast IP for your account.

Verify the CNAME configuration

Use the command line

# 检查 CNAME 记录 dig www.example.com CNAME # 预期输出 ;; ANSWER SECTION: www.example.com. 300 IN CNAME example-com.Sudun.com. # 验证解析 dig www.example.com A # 应解析为 Sudun 边缘节点 IP

Use online tools

• DNS Checker - Check global propagation
• MXToolbox - DNS lookup and diagnostics

From the Sudun Control Panel

1. Go to DNS Resolution domain name list → select your domain name
2. Click Verify DNS
3. Your CNAME configuration will be checked

DNS propagation

DNS changes can take time to propagate globally:

Tips for accelerating dissemination:

1. Lower the TTL to 300 before making the change
2. Wait for the old TTL to expire
3. Make a CNAME change
4. Verify transmission across multiple regions

Multiple CNAME targets

For advanced configurations, you may need different CNAME targets:

FAQs

CNAME conflicts with MX records

If you have configured mail services on the same subdomain:

# 这将无法工作 - CNAME 与 MX 冲突 mail.example.com CNAME example-com.Sudun.com mail.example.com MX mailserver.example.com # 解决方案：为 CDN 使用不同的子域名 cdn.example.com CNAME example-com.Sudun.com

CNAME chains are too long

Avoid creating CNAME chains:

# 错误示例 - 形成链式结构 www.example.com → alias.example.com → example-com.Sudun.com # 正确示例 - 直接 CNAME 指向 www.example.com → example-com.Sudun.com

SSL certificate error after configuring CNAME

If you encounter a certificate error:

1. Make sure that the HTTPS certificate is configured in Sudun
2. Wait for the certificate to be issued (up to 15 minutes may take up)
3. Confirm that the certificate overrides your domain name

Best practices

1. Initial use of low TTL values: It is recommended to set the TTL to 300 seconds for the first configuration
2. Test before go-live: You can use the test subdomain to verify first
3. Continuous monitoring after changes: Observe traffic changes through the control panel
4. Refine DNS record documentation: Maintain a complete record of all DNS configurations
5. Enable DNSSEC: If supported by the platform, it is recommended to enable DNSSEC for enhanced security

API Reference

Configure CNAME settings via API:

# 获取域名的 CNAME 目标地址 curl -X GET https://api.Sudun.com/v1/domains/example.com/dns \ -H "Authorization: Bearer YOUR_API_KEY" # 响应示例 { "cname_target": "example-com.Sudun.com", "status": "active", "verification": "verified" }

Need help configuring DNS? Please contact admin@jindun.com

Adding a domain name to Sudun CDN is the first step in speeding up and securing your website. This guide will walk you through the domain onboarding process.