DNS Record Check
DNS servers store the IP addresses of domains, subdomains and host names as so called A or AAAA-Records. But DNS servers use much more record types. The most important DNS record types are:
| AAAA | IPv6 host address |
| CNAME | Alias of one name to another: the DNS lookup will continue by retrying the lookup with the new name |
| MX | Lists the mail servers authoritative for the domain |
| NS | Authorative Name Servers for this domain |
| SOA | (Start of Authority Record) Information about a DNS zone and it's primary DNS server |
| SRV | Service location record, used to locate Services like IMAP, LDAP or Autodiscover |
| PTR | Canonical name mostly used für Reverse DNS |
| TXT | Text information or arbitrary machine readable data |
Our DNS Record Check reads all DNS records of the requested domain name in realtime. Please note, however, that the list returned in the DNS record section does not contain subdomains, hostnames or CNAMEs because it is technically impossible to publicly and legally query such a list. If you know that a specific hostname exists, you may of course get all the associated DNS records. For example, in order to find out if the hostname www exists, you must enter www.company.com and check if an entry is returned or not. The Internet DNS system is built this way on purpose.
There are a number of hacker websites that promise to find out all subdomains and hostnames of a specific domain, such as Subdomain Finder or DNS Dumpster. Their functioning is quite impressive but it is important to know that the returned data is usually not current and often contain stale entries that don't exist any more in DNS.
References
DNS Resource Records (Wikipedia)