A CNAME (Canonical Name) record is a DNS record that creates an alias, mapping one domain name to another domain name instead of to an IP address.
If you’ve ever set up a website subdomain like www.example.com or connected a custom domain to a third-party service, you’ve likely encountered CNAME records. They’re essential for pointing your branded web address to services you don’t host yourself — especially when setting up branded short links or CDN integrations.
In this guide, you’ll learn what a CNAME record is, how it works, its key technical rules, and exactly how to add one when setting up a custom domain for a URL shortener.
TL;DR
A CNAME record points a subdomain (like links.yourbrand.com) to another domain name (like shortener.example.com), which then resolves to an IP address. This is crucial for branded short URLs because it lets your custom domain act as the shortener’s domain without giving you access to its servers. CNAMEs cannot be used on the root domain (e.g., example.com) and cannot coexist with other record types like MX or TXT on the same hostname.
Key Takeaways
- CNAME stands for Canonical Name — it creates an alias that maps one domain name to another.
- CNAMEs point to domain names, not IP addresses — they resolve in two steps: first to the canonical domain, then to its A record IP.
- They cannot be used on the root domain (the zone apex) because of DNS protocol restrictions — only subdomains can use CNAMEs.
- A CNAME cannot coexist with other record types like MX (email), TXT (verification), or NS on the same hostname.
- For URL shorteners, CNAMEs are essential — they let you use your own domain for branded short links while the shortener’s service handles the redirects.
What Is a CNAME Record in Plain Language?
A CNAME record is like a forwarding address for your domain. Instead of telling the internet “my server’s IP address is 192.0.2.1” (which is what an A record does), a CNAME says “go ask that other domain where the server is.”
Here’s a simple example:
- www.example.com has a CNAME pointing to example.com
- example.com has an A record pointing to the server IP address
When someone visits www.example.com, the DNS system follows the CNAME to example.com, then finds the IP address from the A record. This means if the server IP changes, you only update the A record at example.com — all CNAMEs pointing to it automatically inherit the new IP.
CNAME records are also called “alias records” because that’s exactly what they do — they give a domain a nickname that points to the real name (the canonical name).
How a CNAME Record Works
A CNAME record adds one extra step compared to a regular A record. Here’s what happens behind the scenes:
The Resolution Process
- A DNS resolver receives a query for a domain like links.yourbrand.com
- It finds a CNAME record pointing to shortener.service.com
- It performs a second lookup on shortener.service.com to find its IP address
- It returns the IP address to your browser, completing the request
This two-step process adds a tiny bit of latency on the first lookup, but caching usually eliminates that delay for subsequent requests.
Example CNAME Record
| Hostname | Record Type | Points To |
|---|---|---|
| www.example.com | CNAME | example.com |
| blog.example.com | CNAME | example.com |
| links.yourbrand.com | CNAME | shortener.service.com |
In the last example, links.yourbrand.com acts as an alias for shortener.service.com. Visitors see your branded domain, but the DNS system actually routes them to the service provider’s infrastructure.
Why CNAME Records Are Essential for Branded Short URLs
When you want to create branded short links like links.yourbrand.com/sale, you need a CNAME record. Here’s why:
How It Works for URL Shorteners
Most URL shortener services — including Sinch Engage, Runnr.ai, and many others — require you to create a CNAME record that points your custom domain to their domain.
- You choose a subdomain like links.yourbrand.com for your short links
- You create a CNAME record pointing links.yourbrand.com to the shortener’s domain (like nxt.to or links.runnr.ai)
- You verify the setup — when configured correctly, visiting your custom domain shows the service’s page
- Your branded links start working — links.yourbrand.com/abc123 now redirects to your destination pages
The CNAME record lets you use your own brand in the link without actually hosting the redirect service yourself. The shortener handles all the technical redirect work while your brand takes the credit.
Benefits of This Setup
- Professional appearance — your links display your brand, not the shortener’s domain
- Increased trust — people recognise your domain and are more likely to click
- No server management — the shortener handles all the redirect infrastructure
- Flexibility — if you switch shortener providers, you can update the CNAME record to point to the new service
Key Technical Rules for CNAME Records
There are several important restrictions to understand before adding a CNAME record:
1. CNAME Cannot Be Used on the Root Domain
You cannot create a CNAME record for the zone apex — the bare domain like example.com (without a subdomain like www). This is a DNS protocol restriction, not a hosting limitation.
The root domain must have SOA (Start of Authority) and NS (Name Server) records, and a CNAME cannot coexist with these essential records. Some providers offer non-standard solutions like ALIAS or ANAME records for this use case, but they’re not standard CNAMEs.
Solution: Use a subdomain like links.example.com or www.example.com for your CNAME records.
2. No Other Record Types Can Coexist
If a hostname has a CNAME record, you cannot have any other record types (A, MX, TXT, NS) at that same hostname.
This is a critical limitation because:
- MX records — you cannot receive email at a hostname with a CNAME
- TXT records — you cannot add SPF, DKIM, or DMARC verification at that hostname
- NS records — you cannot delegate subdomains from a CNAME hostname
If you need to receive email at that address, use an A record instead.
3. CNAME Points to Domain Names, Not IP Addresses
CNAME records only accept other domain names as their target value. You cannot enter an IP address. The target domain must be a fully qualified domain name (FQDN) that already exists in DNS.
4. CNAME Chaining Is Possible but Not Recommended
You can point a CNAME to another CNAME, but this adds unnecessary lookup steps and can cause performance issues or even loops.
Best practice: Point CNAMEs directly to the canonical domain that has an A record.
CNAME vs A Record: What’s the Difference?
Understanding the difference between CNAME and A records is essential for proper DNS configuration.
| Feature | A Record | CNAME Record |
|---|---|---|
| Points to | An IP address (like 192.0.2.1) | Another domain name (like example.com) |
| Resolution steps | One step — direct to IP | At least two steps — alias then IP |
| Can be used at root domain | Yes | No — DNS protocol restriction |
| Can coexist with MX/TXT records | Yes | No — CNAME blocks other record types |
| IP changes | Requires manual update of each record | Automatically inherits the canonical target’s IP |
For more detail on how DNS record types work together for link management, see our guide on URL shortener DNS setup.
How to Add a CNAME Record: Step-by-Step
The exact process varies by hosting provider, but these steps cover the general approach:
- Log in to your DNS management dashboard — this is usually with your domain registrar or hosting provider.
- Navigate to the DNS or Zone Editor section — look for options like “DNS Management,” “Zone Editor,” or “Advanced DNS.”
- Add a new record — click “Add Record” or similar.
- Select CNAME as the record type.
- Enter the hostname — this is the subdomain you want to use, like links (for links.yourbrand.com). Do not include the full domain — just the prefix.
- Enter the target value — the full domain name you’re pointing to, such as shortener.service.com.
- Set the TTL (Time to Live) — keep the default or set a low value (like 300 seconds) for testing.
- Save the record.
For URL shortener setup specifically, you’ll typically point your subdomain to the shortener’s domain — for example, links.yourbrand.com → nxt.to or links.yourbrand.com → links.runnr.ai.
Troubleshooting Common Issues
- Propagation delay — DNS changes can take up to 24-48 hours to propagate globally, though most updates complete within minutes to hours.
- Conflicting records — ensure there are no existing A, MX, or TXT records for the same hostname. Remove any conflicting records before adding the CNAME.
- Root domain CNAME — if you need to point the root domain (like yourbrand.com) to a provider’s hostname, check if your DNS provider supports ALIAS or ANAME records as a non-standard alternative.
Frequently Asked Questions
What does CNAME stand for?
CNAME stands for Canonical Name. It’s a DNS record that maps an alias domain to its true, canonical domain name.
Can I use a CNAME record for my root domain?
No. DNS protocol restrictions prevent CNAME records from being used on the root domain (like example.com) because the root must have SOA and NS records that cannot coexist with a CNAME. Some providers offer ALIAS or ANAME records as a workaround.
Can I have a CNAME and MX record for the same hostname?
No. A CNAME cannot coexist with any other record type — including MX — on the same hostname. If you need to receive email at that address, use an A record instead.
How long does a CNAME record take to work?
DNS propagation typically takes anywhere from a few minutes to 48 hours, depending on your DNS provider and TTL settings. Setting a low TTL before making changes can speed up the process.
Why do I need a CNAME record for branded short URLs?
URL shorteners require a CNAME record to route traffic from your custom domain to their service. This lets you use your brand in the link while the shortener handles all the redirect technology behind the scenes.
Sources
- Cornell University — CNAME Record Definition
- Hetzner Docs — CNAME Record Overview
- Vercel — CNAME vs A Record Comparison
- Sinch Engage — Custom Domain Setup with CNAME
- Runnr.ai — Custom Short URL CNAME Setup
Have a question about configuring a CNAME for your branded short links? Drop it in the comments — we’re here to help.
