3.1.5.10. Wildcard entry (*)

In system DNS you can set a default entry for undeclared subdomains. This entry is called a wildcard.

The entry is created by specifying the symbol * in the subdomain field. The principle of operation of such a record is quite simple — if the requested subdomain or its parent was not explicitly specified in any record, then a wildcard record (roughly speaking, the default record) will be taken. This is convenient for setting up a large number of subdomains, since you do not need to add a separate entry for each subdomain. By default when adding or registration domain, two wildcard entries are created: of type A and type AAAA.

Principle of operation

For example, for the domain example.com the following records are created:

Subdomain Type Data
example.com A 1.XXX.XXX.XXX
www.example.com A 1.XXX.XXX.XXX
*.example.com A 2.XXX.XXX.XXX
sub.example.com A 3.XXX.XXX.XXX
*.domain.example.com A 4.XXX.XXX.XXX
form.domain.example.com A 5.XXX.XXX.XXX
anothersub.example.com TXT XXXXXXXXXXXX

In the case described above, the wildcard entry will be valid for any subdomains except sub, anothersub and their subdomains, and for all subdomains domain its wildcard entry will be used. For example:

  • Request for www.example.com will return record 1.XXX.XXX.XXX.
  • Request for sub.example.com will return the record 3.XXX.XXX.XXX.
  • Request for some.sub.example.com will not return an entry because it is not specified. Wildcard entry will not be applied, since the subdomain sub was announced.
  • Request for sub.anothersub.example.com will not return an entry because it is not specified. Wildcard entry will not be applied, since the subdomain anothersub was announced.
  • Request for anothersub.example.com will return the TXT record XXXXXXXXXXXX.
  • Request for like.domain.example.com will return the record 4.XXX.XXX.XXX.
  • Request for domain.example.com will return record 4.XXX.XXX.XXX (wildcard record is used *.domain).
  • Request for form.domain.example.com will return the record 5.XXX.XXX.XXX. Wildcard entry will not be applied, since the subdomain form.domain. was announced.
  • Request for test.example.com will return record 2.XXX.XXX.XXX (wildcard record is used *).
  • Request for sub.www.example.com will not return an entry because it is not specified. Wildcard entry will not be applied, since the subdomain www was announced.
  • Request for poddomen.example.com will return record 2.XXX.XXX.XXX (wildcard record is used *).
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