In its simplest form,
extracts the A
records from the DNS database.
However, it is sometimes interesting (or useful) to use the
command to read the SOA
and other record types as well.
to extract other kinds of records, use the
- Address (A) record: An A record is a type of Resource Record that specifies an IP address-to-host name mapping.
- Pointer (PTR) record: A PTR record is a type of Resource Record that specifies a host name-to-IP address mapping.
- State of Authority (SOA) record: An SOA record is a type of Resource Record that sets basic parameters for a DNS zone of authority and marks the beginning of a zone.
Every zone or subzone must have exactly one SOA record and the zone continues until another SOA record is encountered.
- Host information (HINFO) record: An HINFO record is a type of Resource Record that gives the operating system and architecture for the specified host.
Click the View MouseOver button to look at the output of this command. This information came in a single
In addition to the answer to a particular question, DNS queries contain authority information explaining where the information came from, and
additional information which may be helpful. In our example, the authority information is the name server records,
and the additional information is their IP addresses. This information saves you from having to do an additional A record query.
Note the HINFO record describing the machine raphael.math.uic.edu, together with the authority records and additional information.
System Information Record (HINFO):
This record allows definition of the Hardware type and Operating System (OS) in use at a host.
For security reasons these records are rarely used on public servers. If a space exists in the field it must be enclosed in quotes.
Default Server: dns.class.com
> set type=HINFO
raphael.math.uic.edu CPU = Intel OS = linux
math.uic.edu nameserver = newton.math.uic.edu
math.uic.edu nameserver = dns2.math.uic.edu
math.uic.edu nameserver = uic-dns1.uic.edu
math.uic.edu nameserver = uic-dns2.uic.edu
math.uic.edu nameserver = uic-dns3.uic.edu
newton.math.uic.edu internet address = 188.8.131.52
uic-dns1.uic.edu internet address = 184.108.40.206
uic-dns2.uic.edu internet address = 220.127.116.11
uic-dns3.uic.edu internet address = 18.104.22.168
Click the on the link below for some additional exploration of