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dnsquery(1) |
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DNSQUERY(1) BSD General Commands Manual DNSQUERY(1)
NAME
dnsquery — query domain name servers using resolver
SYNOPSIS
dnsquery [−n nameserver] [−t type] [−c class] [−r retry] [−p period] [−d] [−s] [−v] host
DESCRIPTION
The dnsquery program is a general interface to nameservers via BIND resolver library calls. The program supports queries to the nameserver with an opcode of QUERY. This program is intended to be a replacement or supplement to programs like nstest, nsquery and nslookup. All arguments except for host and nameserver are treated without case-sensitivity.
OPTIONS
−n nameserver
The nameserver to be used in the query. Nameservers can appear as either Internet addresses of the form w.x.y.z or can appear as domain names. (Default: as specified in /etc/resolv.conf.)
−t type
The type of resource record of interest. Types include:
A
address
NS
nameserver
CNAME
canonical name
PTR
domain name pointer
SOA
start of authority
WKS
well-known service
HINFO
host information
MINFO
mailbox information
MX
mail exchange
RP
responsible person
MG
mail group member
AFSDB
DCE or AFS server
ANY
wildcard
Note that any case may be used. (Default: ANY.)
−c class
The class of resource records of interest. Classes include:
IN
Internet
HS
Hesiod
CHAOS
Chaos
ANY
wildcard
Note that any case may be used. (Default: IN.)
−r retry
The number of times to retry if the nameserver is not responding. (Default: 4.)
−p period
Period to wait before timing out. (Default: RES_TIMEOUT.)
−d
Turn on debugging. This sets the RES_DEBUG bit of the resolver’s options field. (Default: no debugging.)
−s
Use a stream rather than a packet. This uses a TCP stream connection with the nameserver rather than a UDP datagram. This sets the RES_USEVC bit of the resolver’s options field. (Default: UDP datagram.)
−v
Synonym for the ’’−s’’ flag.
host
The name of the host (or domain) of interest.
FILES
/etc/resolv.conf
to get the default ns and search lists
<arpa/nameser.h>
list of usable RR types and classes
<resolv.h>
list of resolver flags
DIAGNOSTICS
If the resolver fails to answer the query and debugging has not been turned on, dnsquery will simply print a message like:
Query failed (rc = 1): Unknown host
The value of the return code is supplied by h_errno.
SEE ALSO
nslookup(8), nstest(1), nsquery(1), named(8), resolver(5).
AUTHOR
Bryan Beecher
BUGS
Queries of a class other than IN can have interesting results since ordinarily a nameserver only has a list of root nameservers for class IN resource records.
Dnsquery uses a call to inet_addr() to determine if the argument for the ’’−n’’ option is a valid Internet address. Unfortunately, inet_addr() seems to cause a segmentation fault with some (bad) IP addresses (e.g., 1.2.3.4.5).
4th Berkeley Distribution March 10, 1990 4th Berkeley Distribution
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