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Glossary Web & HTTP

Subdomain

A subdomain is a name placed in front of a domain, such as blog.example.com or www.example.com, that can point to a different server or service.

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In more detail

The owner of example.com can create any number of subdomains with DNS records at no extra cost, to separate a blog, an app or a staging site. Browsers treat each subdomain as a different site for most security rules, but cookies set for the parent domain are shared with all of them. Unused subdomains with leftover DNS records can be hijacked.

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DNS Record Lookup

Look up A, AAAA, MX, TXT, NS, or CNAME DNS records for any domain in real time.

See also

  • Glossary Domain name
    A domain name is the human-readable address of a website or service, such as example.com, which DNS translates into an IP address.
  • Glossary DNS
    DNS (Domain Name System) is the internet's directory that translates domain names like example.com into IP addresses and holds other.
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