This tutorial will teach you how to host a subdomain on Host B, even when the domain is already hosted on Host A. For example, asclaria.org is already hosted on Host A, but spire.asclaria.org is hosted elsewhere.
In this tutorial, cPanel is used. It is the most commonly used administrative panel on web hosting providers, but the interface is generally the same across different panels.
Before we begin, make sure that you have access to the control panel from the domain-side at least, and that you have permission to edit zone records.
Log in to the control panel where the domain is hosted, and go to the Advanced Zone Editor.
Add a new record.
|Name||subdomain.domain.tld. (Make sure to end with a period.)|
|TTL (Time to Live)||14400 (default value)|
|Address||IP Address of the server where the subdomain is hosted|
If you don’t know the IP address of the server your subdomain is on, you can retrieve it by checking the Server Information in the General Information sidebar of the cPanel interface of Host B (the server where your subdomain is going to be hosted). Look for Shared IP Address.
See the image below for a more concrete example.
At this point, the new record should be listed.
Now, all you have to do is to wait for the DNS to propagate. It might take up to 48 hours, but it usually does not take that long. Once the propagation is done, you should be able to access the subdomain!