Hosting Tricks: How to delegate DNS-management for some subdomain to off-site DNS-server
6 Mar2006

In one of my last posts about cheap hosting unlimited number of domains, I have described how to point your domain to some sub-directory of an existing hosting account. But sometimes hosting provider requires parking of your DNS name for creating aliases in hosting account. For example, hosting platform, created by me and used on Free Adult hosting Servik.com service, requires your domain’s NS-records to be directed to provider’s own DNS-servers. What can you do if you don’t want to park entire domain to provider’s DNS-servers and want to host only one sub-domain on its servers?

As a simple, but very powerful solution, I can suggest following trick.

Let’s see to generic DNS-domain configuration. Generic domain has following records:

  • SOA – record with domain contact information, expiring values, etc.
  • NS – record(s) with IP addresses of domain’s DNS-servers.
  • MX – record(s) with IP or symbolic names of domain’s mail servers.
  • A – record(s) with IP addresses of domain and subdomains.
  • CNAME – synonyms for A-records.

When you asking your DNS system for resolving some symbolic name to an IP address and this name is some sub-domain name (such as kovyrin.net or mail.google.com), your DNS server trying to find NS-records for this sub-domain (e.g kovyrin.net) and then, if records were not found, it looks for NS servers for parent domain (kovyrin.net). With generic DNS configuration you can’t allow DNS-management of some sub-domain to off-site DNS-server. You can only move entire domain between DNS-servers.

But let’s try to add following records to your DNS-zone:

    ....
    subdomain.domain.com IN NS off-site.dns-server.com.
    ....

Now, all requests for subdomain.domain.com will be referred to off-site.dns-server.com and this server can freely manage delegated subdomain record by creating another sub-domains or changing this subdomain IP-address.