using your own domain name with greenhouse

If you wish to use your own domain name (lets say it's example.com) with Greenhouse, you must first create a CNAME resource record pointing to your personal greenhouse domain forest.greenhouseusers.com.

In order to do this, you will need to log into whatever service or system is currently managing your DNS records. Most of the time this will be a web-based control panel offered by the domain registrar that you paid to register the domain: namecheap.com, gandi.net, porkbun.com, and njal.la are some examples of registrar companies you may have used.

Sometimes these companies hide the panel you need to access to create this record under the "advanced" tab.

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Note that you can only create a CNAME record for a subdomain on your domain name. According to RFC1034 - Domain Names, a CNAME record can't exist on the "bare" aka "apex" domain.

A concrete example of this: Putting a CNAME on www.example.com is fine, but example.comwould not be allowed.

A domain name is something that you have to register and pay for, like example.com or my-cool-domain.org.

A subdomain is a name you configure under a domain name you control. You can have as many subdomains as you want, they are free as long as you control the domain they are placed under. www.example.com and blog.my-cool-domain.org are examples of subdomains.

That RFC (Request For Comments) specification document was written in 1987, and since then, web developers the world over have yearned for a way to redirect DNS lookups from an apex domain to somewhere else. Domain name companies have responded to this desire in many different ways. Some offer a dynamic A record or "ALIAS record" which can point to a domain name instead of an IP addess.

These solutions work somewhat similar to how a CNAME would while sidestepping the limitation. Some companies like cloudflare misrepresent this "dynamic A record" in thier user interface and refer to it as CNAME, even though it's not actually a CNAME.

Meanwhile, other providers like namecheap have rebelled and decided not to follow the specification, allowing users to create CNAME records on apex domains, even though it might break things.

Luckily, namecheap does also offer an ALIAS record type which is much preferred on apex domains as it is guaranteed to be compatible & should not cause software bugs.

As you can see, this is a bit of a nuanced topic. If you want to use your apex domain, it's probably worth it to research how your DNS provider handles this.

The alternative solution might be to simply not use the apex domain; use a subdomain for your CNAME and then have your DNS provider set up a web-based redirect from the apex domain to the subdomain.

For more information see It is often asked, “Why can’t I have a CNAME at the zone apex?” at the Internet Systems Consortium blog.

configuration example: namecheap

Here are some screenshots documenting the way the DNS records would be created when using namecheap. Other DNS providers will probably look somewhat similar.

Navigate to "Advanced DNS" for your domain:
When configuring a subdomain like www, use a CNAME record:
When configuring the apex domain (represented as @ in DNS software) use an ALIAS record: