DNSQUERY (1)

SYNOPSIS

dnsquery Fl n Ar nameserver Fl t Ar type Fl c Ar class Fl r Ar retry Fl p Ar period Fl d Fl s Fl 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

-tag -width Fl

Fl n Ar 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 . )

Fl t Ar type The type of resource record of interest. Types include: -tag -width "AFSDB " -compact -offset indent

Ar A address

Ar NS nameserver

Ar CNAME canonical name

Ar PTR domain name pointer

Ar SOA start of authority

Ar WKS well-known service

Ar HINFO host information

Ar MINFO mailbox information

Ar MX mail exchange

Ar RP responsible person

Ar MG mail group member

Ar AFSDB DCE or AFS server

Ar ANY wildcard

Note that any case may be used. (Default: ANY . )

Fl c Ar class The class of resource records of interest. Classes include: -tag -width "CHAOS " -compact -offset indent

Ar IN Internet

Ar HS Hesiod

Ar CHAOS Chaos

Ar ANY wildcard

Note that any case may be used. (Default: IN . )

Fl r Ar retry The number of times to retry if the nameserver is not responding. (Default: 4.)

Fl p Ar period Period to wait before timing out. (Default: RES_TIMEOUT . )

Fl d Turn on debugging. This sets the RES_DEBUG bit of the resolver's options field. (Default: no debugging.)

Fl 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.)

Fl v Synonym for the Fl s flag.

Ar host The name of the host (or domain) of interest.

FILES

-tag -width "<arpa/nameser.h> " -compact

Pa /etc/resolv.conf to get the default ns and search lists

Pa <arpa/nameser.h> list of usable RR types and classes

Pa <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 Fl 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).