Hostnames have specific rules on what is or isn’t valid. A valid hostname only consists of letters, numbers, and the special character – (dash).
Here’s an example of a valid hostname: server-01.no-ip.com
General Hostname Guidelines
- A valid hostname must be between 1 and 63 characters per label. A label are the sections between periods.
- A full hostname cannot be more than 253 characters long.
- Labels cannot begin or end with a dash.
- You cannot have more than one dash per label.
- No spaces can be included.
Valid No-IP Hostnames
What constitutes a valid hostname for No-IP is a little different.
- They can contain the letters a-z, numbers 0-9, and the special character – (dash).
- No-IP Free hostnames labels are limited to 19 characters.
- Plus Managed DNS, Enhanced DNS, and Pro Dynamic DNS labels can be up to 49 characters in length.
- Labels cannot begin or end with a dash.
- You cannot have more than one dash within a label.
- No spaces can be included.