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.TH "KDIG" "1" "2026-01-16" "3.5.3" "Knot DNS"
.SH NAME
kdig \- Advanced DNS lookup utility
.SH SYNOPSIS
.sp
\fBkdig\fP [\fIcommon\-settings\fP] [\fIquery\fP [\fIsettings\fP]]...
.sp
\fBkdig\fP \fB\-h\fP
.SH DESCRIPTION
.sp
This utility sends one or more DNS queries to a nameserver. Each query can have
individual \fIsettings\fP, or it can be specified globally via \fIcommon\-settings\fP,
which must precede \fIquery\fP specification.
.SS Parameters
.INDENT 0.0
.TP
.B \fIquery\fP
\fIname\fP | \fB\-q\fP \fIname\fP | \fB\-x\fP \fIaddress\fP | \fB\-G\fP \fItapfile\fP
.TP
.B \fIcommon\-settings\fP, \fIsettings\fP
[\fIquery_class\fP] [\fIquery_type\fP] [\fB@\fP\fIserver\fP]... [\fIoptions\fP]
.TP
.B \fIname\fP
Is a domain name that is to be looked up.
.TP
.B \fIserver\fP
Is a domain name or an IPv4 or IPv6 address of the nameserver to send a query
to. An additional port can be specified using address:port ([address]:port
for IPv6 address), address@port, or address#port notation. A value which begins
with \(aq/\(aq character is considered an absolute UNIX socket path. If no server is
specified, the servers from \fB/etc/resolv.conf\fP are used.
.UNINDENT
.sp
If no arguments are provided, \fBkdig\fP sends NS query for the root
zone.
.SS Query classes
.sp
A \fIquery_class\fP can be either a DNS class name (IN, CH) or generic class
specification \fBCLASS\fP\fIXXXXX\fP where \fIXXXXX\fP is a corresponding decimal
class number. The default query class is IN.
.SS Query types
.sp
A \fIquery_type\fP can be either a DNS resource record type
(A, AAAA, NS, SOA, DNSKEY, ANY, etc.) or one of the following:
.INDENT 0.0
.TP
\fBTYPE\fP\fIXXXXX\fP
Generic query type specification where \fIXXXXX\fP is a corresponding decimal
type number.
.TP
\fBAXFR\fP
Full zone transfer request.
.TP
\fBIXFR=\fP\fIserial\fP
Incremental zone transfer request for specified SOA serial number
(i.e. all zone updates since the specified zone version are to be returned).
.TP
\fBNOTIFY=\fP\fIserial\fP
Notify message with a SOA serial hint specified.
.TP
\fBNOTIFY\fP
Notify message with a SOA serial hint unspecified.
.UNINDENT
.sp
The default query type is A.
.SS Options
.INDENT 0.0
.TP
\fB\-4\fP
Use the IPv4 protocol only.
.TP
\fB\-6\fP
Use the IPv6 protocol only.
.TP
\fB\-b\fP \fIaddress\fP
Set the source IP address of the query to \fIaddress\fP\&. The address must be a
valid address for local interface or :: or 0.0.0.0. An optional port
can be specified in the same format as the \fIserver\fP value.
.TP
\fB\-c\fP \fIclass\fP
An explicit \fIquery_class\fP specification. See possible values above.
.TP
\fB\-d\fP
Enable debug messages.
.TP
\fB\-dd\fP
Enable more verbose debug messages (print Subject Alternative Name).
.TP
\fB\-h\fP, \fB\-\-help\fP
Print the program help.
.TP
\fB\-k\fP \fIkeyfile\fP
Use the TSIG key stored in a file \fIkeyfile\fP to authenticate the request. The
file must contain the key in the same format as accepted by the
\fB\-y\fP option.
.TP
\fB\-p\fP \fIport\fP
Set the nameserver port number or service name to send a query to. The default
port is 53.
.TP
\fB\-q\fP \fIname\fP
Set the query name. An explicit variant of \fIname\fP specification. If no \fIname\fP
is provided, empty question section is set.
.TP
\fB\-t\fP \fItype\fP
An explicit \fIquery_type\fP specification. See possible values above.
.TP
\fB\-V\fP, \fB\-\-version\fP
Print the program version. The option \fB\-VV\fP makes the program
print the compile time configuration summary.
.TP
\fB\-x\fP \fIaddress\fP
Send a reverse (PTR) query for IPv4 or IPv6 \fIaddress\fP\&. The correct name, class
and type is set automatically.
.TP
\fB\-y\fP [\fIalg\fP:]\fIname\fP:\fIkey\fP
Use the TSIG key named \fIname\fP to authenticate the request. The \fIalg\fP
part specifies the algorithm (the default is hmac\-sha256) and \fIkey\fP specifies
the shared secret encoded in Base64.
.TP
\fB\-E\fP \fItapfile\fP
Export a dnstap trace of the query and response messages received to the
file \fItapfile\fP\&.
.TP
\fB\-G\fP \fItapfile\fP
Generate message output from a previously saved dnstap file \fItapfile\fP\&.
.TP
\fB+\fP[\fBno\fP]\fBmultiline\fP
Wrap long records to more lines and improve human readability.
.TP
\fB+\fP[\fBno\fP]\fBshort\fP
Show record data only.
.TP
\fB+\fP[\fBno\fP]\fBgeneric\fP
Use the generic representation format when printing resource record types
and data.
.TP
\fB+\fP[\fBno\fP]\fBcrypto\fP
Display the DNSSEC keys and signatures values in base64, instead of omitting them.
(*)
.TP
\fB+\fP[\fBno\fP]\fBaaflag\fP
Set the AA flag.
.TP
\fB+\fP[\fBno\fP]\fBtcflag\fP
Set the TC flag.
.TP
\fB+\fP[\fBno\fP]\fBrdflag\fP
Set the RD flag. (*)
.TP
\fB+\fP[\fBno\fP]\fBrecurse\fP
Same as \fB+\fP[\fBno\fP]\fBrdflag\fP
.TP
\fB+\fP[\fBno\fP]\fBraflag\fP
Set the RA flag.
.TP
\fB+\fP[\fBno\fP]\fBzflag\fP
Set the zero flag bit.
.TP
\fB+\fP[\fBno\fP]\fBadflag\fP
Set the AD flag. (*)
.TP
\fB+\fP[\fBno\fP]\fBcdflag\fP
Set the CD flag.
.TP
\fB+\fP[\fBno\fP]\fBdoflag\fP
Set the DO flag.
.TP
\fB+\fP[\fBno\fP]\fBdnssec\fP
Same as \fB+\fP[\fBno\fP]\fBdoflag\fP
.TP
\fB+\fP[\fBno\fP]\fBall\fP
Show all packet sections.
.TP
\fB+\fP[\fBno\fP]\fBqr\fP
Show the query packet.
.TP
\fB+\fP[\fBno\fP]\fBheader\fP
Show the packet header. (*)
.TP
\fB+\fP[\fBno\fP]\fBcomments\fP
Show commented section names. (*)
.TP
\fB+\fP[\fBno\fP]\fBopt\fP
Show the EDNS pseudosection. (*)
.TP
\fB+\fP[\fBno\fP]\fBopttext\fP
Try to show unknown EDNS options as text.
.TP
\fB+\fP[\fBno\fP]\fBoptpresent\fP
Show EDNS in presentation format according to the specification in version
\X'tty: link https://www.ietf.org/archive/id/draft-peltan-edns-presentation-format-01.html'\fI\%draft\-peltan\-edns\-presentation\-format\-01\fP\X'tty: link'\&.
.TP
\fB+\fP[\fBno\fP]\fBquestion\fP
Show the question section. (*)
.TP
\fB+\fP[\fBno\fP]\fBanswer\fP
Show the answer section. (*)
.TP
\fB+\fP[\fBno\fP]\fBauthority\fP
Show the authority section. (*)
.TP
\fB+\fP[\fBno\fP]\fBadditional\fP
Show the additional section. (*)
.TP
\fB+\fP[\fBno\fP]\fBtsig\fP
Show the TSIG pseudosection. (*)
.TP
\fB+\fP[\fBno\fP]\fBstats\fP
Show trailing packet statistics. (*)
.TP
\fB+\fP[\fBno\fP]\fBclass\fP
Show the DNS class. (*)
.TP
\fB+\fP[\fBno\fP]\fBttl\fP
Show the TTL value. (*)
.TP
\fB+\fP[\fBno\fP]\fBtcp\fP
Use the TCP protocol (default is UDP for standard query and TCP for AXFR/IXFR).
.TP
\fB+\fP[\fBno\fP]\fBfastopen\fP
Use TCP Fast Open.
.TP
\fB+\fP[\fBno\fP]\fBignore\fP
Don\(aqt use TCP automatically if a truncated reply is received.
.TP
\fB+\fP[\fBno\fP]\fBkeepopen\fP
Keep TCP connection open for the following query if it has the same connection
configuration. This applies to +tcp, +tls, +https, and +quic operations. The connection
is considered in the context of a single kdig call only.
.TP
\fB+\fP[\fBno\fP]\fBtls\fP
Use TLS with the Opportunistic privacy profile (\X'tty: link https://datatracker.ietf.org/doc/html/rfc7858.html#section-4.1'\fI\%RFC 7858 Section 4.1\fP\X'tty: link').
.TP
\fB+\fP[\fBno\fP]\fBtls\-ca\fP[=\fIFILE\fP]
Use TLS with a certificate validation. Certification authority certificates
are loaded from the specified PEM file (default is system certificate storage
if no argument is provided).
Can be specified multiple times. If the +tls\-hostname option is not provided,
the name of the target server (if specified) is used for strict authentication.
.TP
\fB+\fP[\fBno\fP]\fBtls\-pin\fP=\fIBASE64\fP
Use TLS with the Out\-of\-Band key\-pinned privacy profile (\X'tty: link https://datatracker.ietf.org/doc/html/rfc7858.html#section-4.2'\fI\%RFC 7858 Section 4.2\fP\X'tty: link').
The PIN must be a Base64 encoded SHA\-256 hash of the X.509 SubjectPublicKeyInfo.
Can be specified multiple times.
.TP
\fB+\fP[\fBno\fP]\fBtls\-hostname\fP=\fISTR\fP
Use TLS with a remote server hostname check.
.TP
\fB+\fP[\fBno\fP]\fBtls\-sni\fP=\fISTR\fP
Use TLS with a Server Name Indication.
.TP
\fB+\fP[\fBno\fP]\fBtls\-keyfile\fP=\fIFILE\fP
Use TLS with a client keyfile.
.TP
\fB+\fP[\fBno\fP]\fBtls\-certfile\fP=\fIFILE\fP
Use TLS with a client certfile.
.TP
\fB+\fP[\fBno\fP]\fBtls\-ocsp\-stapling\fP[=\fIH\fP]
Use TLS with a valid stapled OCSP response for the server certificate
(%u or specify hours). OCSP responses older than the specified period are
considered invalid.
.TP
\fB+\fP[\fBno\fP]\fBhttps\fP[=\fIURL\fP]
Use HTTPS (DNS\-over\-HTTPS) in wire format (\X'tty: link https://datatracker.ietf.org/doc/html/rfc1035.html#section-4.2.1'\fI\%RFC 1035 Section 4.2.1\fP\X'tty: link').
It is also possible to specify URL=[authority][/path] where request
will be sent to. Any leading scheme and authority indicator (i.e. //) are ignored.
Authority might also be specified as the \fIserver\fP (using the parameter \fI@\fP).
If \fIpath\fP is specified and \fIauthority\fP is missing, then the \fIserver\fP
is used as authority together with the specified \fIpath\fP\&.
Library \fIlibnghttp2\fP is required.
.TP
\fB+\fP[\fBno\fP]\fBhttps\-get\fP
Use HTTPS with HTTP/GET method instead of the default HTTP/POST method.
Library \fIlibnghttp2\fP is required.
.TP
\fB+\fP[\fBno\fP]\fBquic\fP
Use QUIC (DNS\-over\-QUIC).
.TP
\fB+\fP[\fBno\fP]\fBnsid\fP
Request the nameserver identifier (NSID).
.TP
\fB+\fP[\fBno\fP]\fBzoneversion\fP
Request the EDNS zone version.
.TP
\fB+\fP[\fBno\fP]\fBbufsize\fP=\fIB\fP
Set EDNS buffer size in bytes (default is 1232 bytes).
.TP
\fB+\fP[\fBno\fP]\fBpadding\fP[=\fIB\fP]
Use EDNS(0) padding option to pad queries, optionally to a specific
size. The default is to pad queries with a sensible amount when using
+tls, and not to pad at all when queries are sent without TLS.  With
no argument (i.e., just +padding) pad every query with a sensible
amount regardless of the use of TLS. With +nopadding, never pad.
.TP
\fB+\fP[\fBno\fP]\fBalignment\fP[=\fIB\fP]
Align the query to B\-byte\-block message using the EDNS(0) padding option
(default is no or 128 if no argument is specified).
.TP
\fB+\fP[\fBno\fP]\fBsubnet\fP=\fISUBN\fP
Set EDNS(0) client subnet SUBN=addr/prefix.
.TP
\fB+\fP[\fBno\fP]\fBedns\fP[=\fIN\fP]
Use EDNS version (default is 0).
.TP
\fB+\fP[\fBno\fP]\fBmsgdelay\fP=\fIT\fP
Wait the specified number of milliseconds before receiving each AXFR/IXFR message.
.TP
\fB+\fP[\fBno\fP]\fBtimeout\fP=\fIT\fP
Set the wait\-for\-reply interval in seconds (default is 5 seconds). This timeout
applies to each query attempt. Zero value or \fInotimeout\fP is interpreted as
infinity.
.TP
\fB+\fP[\fBno\fP]\fBretry\fP=\fIN\fP
Set the number (>=0) of UDP retries (default is 2). This doesn\(aqt apply to
AXFR/IXFR.
.TP
\fB+\fP[\fBno\fP]\fBexpire\fP
Sets the EXPIRE EDNS option.
.TP
\fB+\fP[\fBno\fP]\fBcookie\fP[=\fIHEX\fP]
Attach EDNS(0) cookie to the query.
.TP
\fB+\fP[\fBno\fP]\fBbadcookie\fP
Repeat a query with the correct cookie.
.TP
\fB+\fP[\fBno\fP]\fBednsopt\fP[=\fICODE\fP[:\fIHEX\fP]]
Send custom EDNS option. The \fICODE\fP is EDNS option code in decimal, \fIHEX\fP
is an optional hex encoded string to use as EDNS option value. This argument
can be used multiple times. +noednsopt clears all EDNS options specified by
+ednsopt.
.TP
\fB+\fP[\fBno\fP]\fBproxy\fP=\fISRC_ADDR\fP[#\fISRC_PORT\fP]\-\fIDST_ADDR\fP[#\fIDST_PORT\fP]
Add PROXYv2 header with the specified source and destination addresses to the query.
The default source port is 0 and destination port 53.
.TP
\fB+\fP[\fBno\fP]\fBjson\fP
Use JSON for output encoding (RFC 8427).
.TP
\fB+noidn\fP
Disable the IDN transformation to ASCII and vice versa. IDN support depends
on libidn2 availability during project building! If used in \fIcommon\-settings\fP,
all IDN transformations are disabled. If used in the individual query \fIsettings\fP,
transformation from ASCII is disabled on output for the particular query. Note
that IDN transformation does not preserve domain name letter case.
.UNINDENT
.SH NOTES
.sp
By default, only options marked with (*) are enabled.
.sp
Options \fB\-k\fP and \fB\-y\fP can not be used simultaneously.
.sp
Dnssec\-keygen keyfile format is not supported. Use \fBkeymgr(8)\fP instead.
.SH EXIT VALUES
.sp
Exit status of 0 means successful operation. Any other exit status indicates
an error.
.SH EXAMPLES
.INDENT 0.0
.IP 1. 3
Get A records for example.com:
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig example.com A
.EE
.UNINDENT
.UNINDENT
.IP 2. 3
Perform AXFR for zone example.com from the server 192.0.2.1:
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig example.com \-t AXFR @192.0.2.1
.EE
.UNINDENT
.UNINDENT
.IP 3. 3
Get A records for example.com from 192.0.2.1 and reverse lookup for address
2001:DB8::1 from 192.0.2.2. Both using the TCP protocol:
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig +tcp example.com \-t A @192.0.2.1 \-x 2001:DB8::1 @192.0.2.2
.EE
.UNINDENT
.UNINDENT
.IP 4. 3
Get SOA record for example.com, use TLS, use system certificates, check
for specified hostname, check for certificate pin, and print additional
debug info:
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig \-d @185.49.141.38 +tls\-ca +tls\-host=getdnsapi.net \e
  +tls\-pin=foxZRnIh9gZpWnl+zEiKa0EJ2rdCGroMWm02gaxSc9S= soa example.com
.EE
.UNINDENT
.UNINDENT
.IP 5. 3
DNS over HTTPS examples (various DoH implementations):
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig @1.1.1.1 +https example.com.
$ kdig @193.17.47.1 +https=/doh example.com.
$ kdig @8.8.4.4 +https +https\-get example.com.
$ kdig @8.8.8.8 +https +tls\-hostname=dns.google +fastopen example.com.
.EE
.UNINDENT
.UNINDENT
.IP 6. 3
More queries share one DoT connection:
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig @1.1.1.1 +tls +keepopen abc.example.com A mail.example.com AAAA
.EE
.UNINDENT
.UNINDENT
.IP 7. 3
Query the name server identifier and version according to \X'tty: link https://datatracker.ietf.org/doc/html/rfc4892.html'\fI\%RFC 4892\fP\X'tty: link':
.INDENT 3.0
.INDENT 3.5
.sp
.EX
$ kdig @a.iana\-servers.net. CH TXT id.server version.server
.EE
.UNINDENT
.UNINDENT
.UNINDENT
.SH FILES
.sp
\fB/etc/resolv.conf\fP
.SH SEE ALSO
.sp
\fBkhost(1)\fP, \fBknsupdate(1)\fP, \fBkeymgr(8)\fP\&.
.SH AUTHOR
CZ.NIC, z.s.p.o. and contributors <https://www.knot-dns.cz/>
.SH COPYRIGHT
Copyright (C) CZ.NIC, z.s.p.o. and contributors
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