Available on every Dynamic DNS plan: Free (5 hostnames), Pro (100) and Elite (500).
1. What This Feature Does
A Dynamic DNS hostname is a name, such as home.example.com, that points at an IP address you can change at any time — from the dashboard, or automatically from your router or a script when your internet connection gets a new address.
Each hostname holds one address: IPv4 (an A record) or IPv6 (an AAAA record). You can create it on one of the CertaDNS domains offered in the dashboard, or on a domain of your own that is on Managed DNS.
2. When You Should Use It
- You reach a home server, NAS, camera or game server by name, and your provider changes your public IP address from time to time.
- You connect to a remote network over VPN or SSH and want a name instead of an address you have to look up.
- You want a router or script to keep the name current without you.
3. When You Should Not Use It
- You need records other than A or AAAA (MX, CNAME, TXT and so on). Put the domain on Managed DNS and use DNS records.
- You only want a name to send visitors to a web address. Create the hostname, then use Web Forwarding.
4. Prerequisites
- A CertaDNS account with a confirmed email address.
- For a hostname on your own domain: that domain on Managed DNS in your account.
- Accounts managed by an organization cannot create personal hostnames; the organization owner manages them.
5. How It Works (Brief)
When you add a hostname, CertaDNS publishes its address on the CertaDNS nameservers straight away. When you change the address, the record is replaced. Resolvers that already looked the name up keep the old answer until it expires — this is the record's TTL, set by your plan:
| Plan | TTL |
|---|---|
| Free | 3600 seconds (one hour) |
| Pro, Elite | 60 seconds |
The TTL is applied each time the address is set, so it follows your plan when you upgrade or downgrade. It cannot be set per hostname.
6. How to Use It
Everything below is in Dynamic DNS in the dashboard sidebar. The page header shows how many hostnames you have and your plan's limit, for example 3 of 5 hostnames used.
Add a hostname
- Click Add hostname (or Add your first hostname on an empty account). The button is disabled once you reach your plan's limit.
- Enter the Subdomain, for example
home. Dots make a multi-level name, for exampledev.home. - Choose the Zone: a CertaDNS domain (under CertaDNS Zones) or one of your own (under Your Imported Zones).
- Choose the Record Type: A (IPv4) or AAAA (IPv6).
- Enter the IP Address. It starts filled in with the address you are browsing from; Use Current puts it back.
- Click Add Hostname. The hostname appears in the list and resolves straight away.
Change a hostname's address
- Click Update IP (pencil icon) on the hostname.
- In Edit record, enter the New address, or click Use my current IP.
- Click Save. The button reads No change until the address differs from the current one.
To keep the address current automatically, set up your router or a script: see DDNS Update Protocols. Update Instructions (question-mark icon) shows the settings for that hostname.
Delete a hostname
Click Delete (trash icon) and confirm with Delete hostname. The hostname stops resolving immediately. This cannot be undone.
Work on several hostnames at once
- Tick the hostnames, or tick the box in the header to select every hostname on the page.
- Update All to <your address> sets them all to the address you are browsing from; hostnames that already have it are skipped.
- Delete Selected lists what will be deleted and asks you to type
deleteto confirm. - Clear deselects everything.
If some hostnames fail, a summary names them.
Find a hostname
Search by name or address, filter with All hostnames, On a CertaDNS domain, On my own domain, Wildcards or Monitored only, and sort by name, IP, type or status. With more hostnames than fit on one page, choose 10, 25, 50 or 100 per page.
7. Inputs and Settings
| Field | Rules |
|---|---|
| Subdomain | Lower-case letters, digits, hyphens and dots. Each part (between dots) up to 63 characters and cannot start or end with a hyphen. The full hostname can be up to 253 characters. |
| Zone | A CertaDNS domain offered in the list, or one of your Managed DNS domains. Some CertaDNS domains are offered on Pro and Elite only. |
| Record Type | A (IPv4) or AAAA (IPv6). Fixed once the hostname is created; to switch, delete the hostname and add it again. |
| IP Address | An IPv4 address for A, an IPv6 address for AAAA. |
On CertaDNS domains, some single-word names are reserved. Multi-level names (such as dev.home) and names on your own domains are not restricted.
8. Outputs and Results
| Column | Shows |
|---|---|
| Domain | The full hostname. Wildcard hostnames carry a Wildcard badge. |
| Zone | The domain it sits under. |
| Status | Active or Inactive. |
| Current IP | The address it points at, or Not set. |
| Monitoring | On or Off; click to switch uptime monitoring for the hostname. |
| Actions | Create Wildcard (sparkle icon; Pro and Elite), Update IP, Update Instructions, Delete. |
9. How to Interpret Results
Normal
- Active with the address you expect in Current IP.
- A lookup still returning the old address for up to the TTL after a change.
Worth investigating
- The address changes back on its own — a router or script is still updating the hostname with a different address.
- A private address (192.168.x.x, 10.x.x.x) in Current IP — a device sent its local address instead of your public one.
Common mistakes
- Expecting every resolver to see a change at once. Up to one hour on Free, up to 60 seconds on Pro and Elite.
- Using the first part of the name on a router (
home) instead of the full hostname (home.example.com).
10. Common Issues and Explanations
"Domain cap reached for your … plan"
You have as many hostnames as your plan allows. Delete one, or move to a plan with more.
"The subdomain '…' is restricted: …"
That single-word name is reserved on CertaDNS domains. Choose another, use a multi-level name, or use your own domain.
"Zone … is available on paid plans only"
That CertaDNS domain is part of Pro and Elite.
"That is an IPv6 address. Use an AAAA record for IPv6…" (or the IPv4 version)
The address does not match the record type you chose. Change one or the other.
Edit record says "This is an A (IPv4) record" for an IPv6 hostname
Change the address of an AAAA hostname with an update from a router or script instead: see DDNS Update Protocols.
The dashboard shows the new address but a lookup does not
The old answer is cached. Wait for the TTL to pass and look again.
Add hostname is disabled
You have reached your plan's hostname limit.
11. Limits and Constraints
| Constraint | Free | Pro | Elite |
|---|---|---|---|
| Hostnames | 5 | 100 | 500 |
| TTL | 3600 s | 60 s | 60 s |
| Record types | A, AAAA | A, AAAA | A, AAAA |
| Wildcard hostnames | No | Yes | Yes |
| Updates with an API key | No | Yes | Yes |
- One address per hostname.
- Wildcard hostnames count toward your hostname total.
- Updates from routers and scripts with your account email and password work on every plan.
12. Related Features
- DDNS Update Protocols — keeping a hostname current from a router or script.
- Wildcard Hostnames — one record for every name under a hostname.
- Web Forwarding — sending a hostname's visitors to a web address.
- Managed DNS — hosting your own domain, so hostnames can sit under it.
- API Keys — for scripts that update hostnames.
13. Updates and Behavior Changes
- 30 September 2026. Changing an address in the dashboard now sets the 60-second TTL on Pro and Elite, as router updates already did. Before, dashboard changes set 3600 seconds on every plan.
- 30 September 2026. This article now describes the Free, Pro and Elite plans; the Plus plan named in earlier versions is no longer offered.
- September 2026. Addresses are changed in the Edit record dialog, which checks the address before saving, instead of a browser prompt.