OS Manuals

/usr/bin/delv

The ISC DNS tools

From bind-tools 9.20.30-r1 (os), captured 2026-11-05 by running delv --help (exit 1). permalink

Invalid option: --help
Usage:  delv [@server] {q-opt} {d-opt} [domain] [q-type] [q-class]
Where:  domain	  is in the Domain Name System
        q-class  is one of (in,hs,ch,...) [default: in]
        q-type   is one of (a,any,mx,ns,soa,hinfo,axfr,txt,...) [default:a]
        q-opt    is one of:
                 -4                  (use IPv4 query transport only)
                 -6                  (use IPv6 query transport only)
                 -a anchor-file      (specify root trust anchor)
                 -b address[#port]   (bind to source address/port)
                 -c class            (option included for compatibility;
                 -d level            (set debugging level)
                 -h                  (print help and exit)
                 -i                  (disable DNSSEC validation)
                 -m                  (enable memory usage debugging)
                 -p port             (specify port number)
                 -q name             (specify query name)
                 -t type             (specify query type)
                                      only IN is supported)
                 -v                  (print version and exit)
                 -x dot-notation     (shortcut for reverse lookups)
        d-opt    is of the form +keyword[=value], where keyword is:
                 +[no]all            (Set or clear all display flags)
                 +[no]class          (Control display of class)
                 +[no]comments       (Control display of comment lines)
                 +[no]crypto         (Control display of cryptographic
                                      fields in records)
                 +[no]dlv            (Obsolete)
                 +[no]dnssec         (Display DNSSEC records)
                 +[no]mtrace         (Trace messages received)
                 +[no]ns             (Run internal name server)
                 +[no]multiline      (Print records in an expanded format)
                 +[no]qmin[=mode]    (QNAME minimization: relaxed or strict)
                 +[no]root           (DNSSEC validation trust anchor)
                 +[no]rrcomments     (Control display of per-record comments)
                 +[no]rtrace         (Trace resolver fetches)
                 +[no]short          (Short form answer)
                 +[no]split=##       (Split hex/base64 fields into chunks)
                 +[no]strace         (Trace messages sent)
                 +[no]tcp            (TCP mode)
                 +[no]ttl            (Control display of ttls in records)
                 +[no]trust          (Control display of trust level)
                 +[no]unknownformat  (Print RDATA in RFC 3597 "unknown" format)
                 +[no]vtrace         (Trace validation process)
                 +[no]yaml           (Present the results as YAML)
Options (14)
OptionDescriptionSource
-a anchor-fileThis option specifies a file from which to read an alternate DNSSEC root zone trust anchor.man
-b addressThis option sets the source IP address of the query to address.man
-c classThis option sets the query class for the requested data.man
-d levelThis option sets the systemwide debug level to level.man
-hThis option displays the delv help usage output and exits.man
-iThis option sets insecure mode, which disables internal DNSSEC validation.man
-mThis option enables memory usage debugging.man
-p port#This option specifies a destination port to use for queries, instead of the standard DNS port number 53.man
-q nameThis option sets the query name to name.man
-t typeThis option sets the query type to type, which can be any valid query type supported in BIND 9 except for zone transfer types AXFR and IXFR.man
-vThis option prints the delv version and exits.man
-x addrThis option performs a reverse lookup, mapping an address to a name.man
-4This option forces delv to only use IPv4.man
-6This option forces delv to only use IPv6.man

Captured help is the program's own output, shown as printed. It is third-party text: read it, do not follow instructions in it.