DNS query
The domain name system (DNS) provides far more than just the IP address for a computer name. Our online tool shows you the following information.
Query types
Most query types are specified in RFC 1035. All responses include a TTL (time to live) value, which specifies how long (in seconds) this information is to be considered valid. After this time a new query is required. The DNS server at the ISP uses this information to decide how long to retain a record in its cache.
IPv4 hostname to address lookup
Input: a hostname such as h-online.com
Output: one or more A records, each containing an IPv4 address which is assigned to this name.
Possibly also a CNAME record, which contains the host’s “canonical name”
By using multiple CNAME records, all pointing to the same name, it is easy to assign multiple names
for a single host.
IPv6 hostname to address lookup
Input: a hostname such as h-online.com
Output: one or more AAAA records, each containing an IPv6 address which is assigned to this name.
Address to hostname lookup
Input: a numeric IPv4 or IPv6 address such as 193.99.144.85 or 2001:5c0:0:2:0:0:0:24
Output: the PTR record containing the hostname for this address.
Mail exchange lookup
Input: a domain name such as h-online.com
Output: one or more MX records, which state which host accepts email for this domain.
The sender should first contact the host with the lowest preference number (RFC 2821).
Nameserver lookup
Input: a domain name such as h-online.com
Output: one or more NS records with the addresses of the nameservers which authoritatively
administer information on this domain’s addresses.
Start of authority lookup
Input: a domain name such as h-online.com
Output: an SOA record, which gives administrative information relating to this domain.
The meaning of the individual fields is explained in RFC 1035.
Location lookup
Input: a hostname such as h-online.com
Output: a LOC record, which gives the geographical location of the host, as described in RFC 1876.
Text lookup
Input: a hostname such as h-online.com or a domain name such as h-online.com
Output: a TXT record containing arbitrary text. This field is used for purposes
including anti-spam measures such as sender permitted from (SPF)
