0

I have a shared hosting service where domainA.com and domainB.com share the same IP address. Each of them have a wildcard DNS entry, *.domainA.com and *.domainB.com.

When domainA.com registers the DNS entry subA.domainA.com then it's automatically available at subA.domainB.com.

How can I prevent this? I would prefer a DNS configuration solution. If that's not possible, is the solution simply to provide a separate dedicated IP address to each domain, even though it's all pointing to the same application?

I know that domainB.com can turn around and register that same subdomain and then end users won't see domainA.com's implementation, but that seems impractical given the very infinite nature of *.

If there are ways I may be missing, please enlighten

Improve this question
2
  • 1
    When domainA.com registers the DNS entry subA.domainA.com then it's automatically available at subA.domainB.com.: this is not standard at all. Therefore, there could be no generic answer. At least, you have to understand why it "registers" like that. If you want us to help you understand the underlying mechanism, share more details: what's DNS server software runs those domains? What kind of wildcard entries they have (what's in both zones)?
    – Nikita Kipriyanov
    Commented Oct 31, 2021 at 16:01
  • This should not be happening, unless you have errors in your zone file. Please include it your post.
    – harrymc
    Commented Oct 31, 2021 at 21:18

1 Answer 1

Reset to default
1

The only way you can prevent this completely is by removing the wildcards. That's literally what wildcards do: their purpose is to automatically "register" all subdomains that aren't already registered explicitly.

If all your subdomains are being added to DNS individually, then the wildcards serve no purpose anyway.

But if it is impossible to remove the wildcards for some reason, then it falls on the web server (i.e. Apache or other HTTP service) to pay better attention to the HTTP vhosts being requested and not serve the website for the incorrect domain. While the web server cannot outright refuse connection, it can still return a generic "No such website" page in this case.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .