Provided by: dirmngr_2.4.4-2ubuntu21_amd64 bug

NAME

       dirmngr - GnuPG's network access daemon

SYNOPSIS

       dirmngr [options] command [args]

DESCRIPTION

       Since  version  2.1  of GnuPG, dirmngr takes care of accessing the OpenPGP keyservers.  As
       with previous versions  it  is  also  used  as  a  server  for  managing  and  downloading
       certificate   revocation   lists   (CRLs)   for   X.509  certificates,  downloading  X.509
       certificates, and providing access to OCSP providers.  Dirmngr is  invoked  internally  by
       gpg, gpgsm, or via the gpg-connect-agent tool.

COMMANDS

       Commands  are  not distinguished from options except for the fact that only one command is
       allowed.

       --version
              Print the  program  version  and  licensing  information.   Note  that  you  cannot
              abbreviate this command.

       --help, -h
              Print  a usage message summarizing the most useful command-line options.  Note that
              you cannot abbreviate this command.

       --dump-options
              Print a list  of  all  available  options  and  commands.   Note  that  you  cannot
              abbreviate this command.

       --server
              Run  in  server  mode  and  wait for commands on the stdin.  The default mode is to
              create a socket and listen for commands there.  This is only used for testing.

       --daemon
              Run in background daemon mode and listen for commands on a socket.  This is the way
              dirmngr  is  started  on  demand  by the other GnuPG components.  To force starting
              dirmngr it is in general best to use gpgconf --launch dirmngr.

       --supervised
              Run in the foreground, sending logs to stderr, and listening on file descriptor  3,
              which  must  already be bound to a listening socket.  This option is deprecated and
              not supported on Windows.

       --list-crls
              List the contents of the CRL cache on stdout. This  is  probably  only  useful  for
              debugging purposes.

       --load-crl file
              This  command  requires a filename as additional argument, and it will make Dirmngr
              try to import the CRL in file into it's cache.  Note, that this is only possible if
              Dirmngr  is  able  to  retrieve the CA's certificate directly by its own means.  In
              general it is better to use gpgsm's --call-dirmngr loadcrl filename command so that
              gpgsm can help dirmngr.

       --fetch-crl url
              This  command  requires an URL as additional argument, and it will make dirmngr try
              to retrieve and import the CRL from that url  into  it's  cache.   This  is  mainly
              useful  for debugging purposes.  The dirmngr-client provides the same feature for a
              running dirmngr.

       --shutdown
              This commands shuts  down  an  running  instance  of  Dirmngr.   This  command  has
              currently no effect.

       --flush
              This  command  removes  all  CRLs  from Dirmngr's cache.  Client requests will thus
              trigger reading of fresh CRLs.

OPTIONS

       Note that all long options with the exception of --options and --homedir may also be given
       in the configuration file after stripping off the two leading dashes.

       --options file
              Reads  configuration  from  file instead of from the default per-user configuration
              file.  The default configuration file is named ‘dirmngr.conf’ and expected  in  the
              home directory.

       --homedir dir
              Set the name of the home directory to dir.  This option is only effective when used
              on the command line.  The default is the directory named  ‘.gnupg’  directly  below
              the  home  directory of the user unless the environment variable GNUPGHOME has been
              set in which case its value will be used.  Many kinds of  data  are  stored  within
              this directory.

       -v

       --verbose
              Outputs  additional  information  while running.  You can increase the verbosity by
              giving several verbose commands to dirmngr, such as -vv.

       --log-file file
              Append all logging output to file.  This is very helpful in seeing what  the  agent
              actually does.  Use ‘socket://’ to log to socket.

       --compatibility-flags flags
              Set  compatibility  flags  to work around certain problems or to emulate bugs.  The
              flags are given as a comma separated list of flag names  and  are  OR-ed  together.
              The  special flag "none" clears the list and allows one to start over with an empty
              list.  To get a list of available flags the sole word "help" can be used.

       --faked-system-time epoch
              This option is only useful for testing; it sets the system time back  or  forth  to
              epoch  which  is  the number of seconds elapsed since the year 1970.  Alternatively
              epoch may be given as a full ISO time string (e.g. "20070924T154812").

       --debug-level level
              Select the debug level for investigating problems.  level may be a numeric value or
              by a keyword:

              none   No  debugging  at  all.   A  value of less than 1 may be used instead of the
                     keyword.

              basic  Some basic debug messages.  A value between 1 and 2 may be used  instead  of
                     the keyword.

              advanced
                     More verbose debug messages.  A value between 3 and 5 may be used instead of
                     the keyword.

              expert Even more detailed messages.  A value between 6 and 8 may be used instead of
                     the keyword.

              guru   All  of  the  debug messages you can get. A value greater than 8 may be used
                     instead of the keyword.  The creation of hash tracing files is only  enabled
                     if the keyword is used.

       How  these  messages  are  mapped  to  the actual debugging flags is not specified and may
       change with newer releases of this program. They are however carefully  selected  to  best
       aid in debugging.

       --debug flags
              Set  debug  flags.   All  flags  are or-ed and flags may be given in C syntax (e.g.
              0x0042) or as a comma separated list of flag names.  To get a list of all supported
              flags the single word "help" can be used.  This option is only useful for debugging
              and the behavior may change at any time without notice.

       --debug-all
              Same as --debug=0xffffffff

       --tls-debug level
              Enable debugging of the TLS layer at level.  The details of the debug level  depend
              on the used TLS library and are not set in stone.

       --debug-wait n
              When  running  in server mode, wait n seconds before entering the actual processing
              loop and print the pid.  This gives time to attach a debugger.

       --disable-check-own-socket
              On some platforms dirmngr is able to detect the removal  of  its  socket  file  and
              shutdown itself.  This option disable this self-test for debugging purposes.

       -s
       --sh
       -c
       --csh  Format  the  info  output  in  daemon  mode  for use with the standard Bourne shell
              respective the C-shell. The default  is  to  guess  it  based  on  the  environment
              variable SHELL which is in almost all cases sufficient.

       --force
              Enabling  this  option  forces  loading  of  expired  CRLs; this is only useful for
              debugging.

       --use-tor
       --no-use-tor
              The option --use-tor switches Dirmngr and thus GnuPG into ``Tor mode'' to route all
              network access via Tor (an anonymity network).  Certain other features are disabled
              in this mode.  The effect of --use-tor cannot be overridden by any other command or
              even  by  reloading dirmngr.  The use of --no-use-tor disables the use of Tor.  The
              default is to use Tor if it is available on startup  or  after  reloading  dirmngr.
              The  test  on the availability of Tor is done by trying to connect to a SOCKS proxy
              at either port 9050 or 9150; if another type of proxy is listening on one of  these
              ports, you should use --no-use-tor.

       --standard-resolver
              This  option  forces  the  use of the system's standard DNS resolver code.  This is
              mainly used for debugging.  Note that on Windows a standard resolver  is  not  used
              and  all  DNS  access  will  return the error ``Not Implemented'' if this option is
              used.  Using this together with enabled Tor mode returns the error ``Not Enabled''.

       --recursive-resolver
              When possible use a recursive resolver instead of a stub resolver.

       --resolver-timeout n
              Set the timeout for the DNS resolver to N seconds.  The default are 30 seconds.

       --connect-timeout n

       --connect-quick-timeout n
              Set the timeout for HTTP and generic TCP connection attempts  to  N  seconds.   The
              value  set with the quick variant is used when the --quick option has been given to
              certain Assuan commands.  The quick value is capped at the  value  of  the  regular
              connect  timeout.   The default values are 15 and 2 seconds.  Note that the timeout
              values are for each connection attempt; the connection code will attempt to connect
              all addresses listed for a server.

       --listen-backlog n
              Set the size of the queue for pending connections.  The default is 64.

       --allow-version-check
              Allow  Dirmngr  to connect to https://versions.gnupg.org to get the list of current
              software versions.  On debian-packaged versions, this  option  does  nothing  since
              software   updates   should  be  handled  by  the  distribution.   See  the  option
              --query-swdb of the command gpgconf for more details.   Note,  that  regardless  of
              this option a version check can always be triggered using this command:

                gpg-connect-agent --dirmngr 'loadswdb --force' /bye

       --keyserver name
              Use  name  as  your  keyserver.   This  is the server that gpg communicates with to
              receive keys, send keys, and search for keys.  The format of the  name  is  a  URI:
              `scheme:[//]keyservername[:port]'  The  scheme  is the type of keyserver: "hkp" for
              the HTTP (or compatible) keyservers or "ldap" for the LDAP  keyservers.  Note  that
              your  particular  installation of GnuPG may have other keyserver types available as
              well. Keyserver schemes are case-insensitive. After the  keyserver  name,  optional
              keyserver  configuration  options  may  be  provided.   These  are  the same as the
              --keyserver-options of gpg, but apply only to this particular keyserver.

              Some keyservers synchronize with each other, so there is not always a need to  send
              keys  to  more  than  one  server.  Some  keyservers  use round robin DNS to give a
              different keyserver each time you use it.

              If exactly two keyservers are configured and only  one  is  a  Tor  hidden  service
              (.onion),  Dirmngr selects the keyserver to use depending on whether Tor is locally
              running or not.  The check for a running Tor is done for each new connection.

              If no keyserver is explicitly configured, dirmngr will use the built-in default  of
              hkps://keys.openpgp.org.   To  avoid  the use of a default keyserver the value none
              can be used.

              Note that the above default is a Debian-specific choice.   Upstream  GnuPG  prefers
              hkps://keys.openpgp.org.    See   /usr/share/doc/gpgconf/NEWS.Debian.gz   for  more
              details.

              Windows users with a keyserver running on their Active Directory may use the  short
              form ldap:/// for name to access this directory.

              For   accessing   anonymous   LDAP   keyservers   name   is   in   general  just  a
              ldaps://ldap.example.com.  A  BaseDN  parameter  should  never  be  specified.   If
              authentication  is  required  things  are  more  complicated  and  two  methods are
              available:

              The modern method (since version 2.2.28) is to use the very  same  syntax  as  used
              with  the  option  --ldapserver.   Please  see  over  there for details; here is an
              example:

                keyserver ldap:ldap.example.com::uid=USERNAME,ou=GnuPG Users,
                dc=example,dc=com:PASSWORD::starttls

              The other method is to use a full URL for name; for example:

                keyserver ldaps://ldap.example.com/????bindname=uid=USERNAME
                %2Cou=GnuPG%20Users%2Cdc=example%2Cdc=com,password=PASSWORD

              Put this all on one line without any spaces and keep the '%2C'
              as given.  Replace USERNAME, PASSWORD, and the 'dc' parts
              according to the instructions received from your LDAP
              administrator.  Note that only simple authentication
              (i.e. cleartext passwords) is supported and thus using ldaps is
              strongly suggested (since 2.2.28 "ldaps" defaults to port 389
              and uses STARTTLS).  On Windows authentication via AD can be
              requested by adding gpgNtds=1 after the fourth question
              mark instead of the bindname and password parameter.

       --nameserver ipaddr
              In ``Tor mode'' Dirmngr uses a public resolver via Tor to resolve  DNS  names.   If
              the  default  public  resolver, which is 8.8.8.8, shall not be used a different one
              can be given using this option.  Note that a numerical IP  address  must  be  given
              (IPv6 or IPv4) and that no error checking is done for ipaddr.

       --disable-ipv4

       --disable-ipv6
              Disable the use of all IPv4 or IPv6 addresses.

       --disable-ldap
              Entirely disables the use of LDAP.

       --disable-http
              Entirely disables the use of HTTP.

       --ignore-http-dp
              When  looking  for  the  location  of  a  CRL, the to be tested certificate usually
              contains so called CRL Distribution Point (DP) entries which  are  URLs  describing
              the way to access the CRL.  The first found DP entry is used.  With this option all
              entries using the HTTP scheme are ignored when looking for a suitable DP.

       --ignore-ldap-dp
              This is similar to --ignore-http-dp but ignores  entries  using  the  LDAP  scheme.
              Both options may be combined resulting in ignoring DPs entirely.

       --ignore-ocsp-service-url
              Ignore  all OCSP URLs contained in the certificate.  The effect is to force the use
              of the default responder.

       --honor-http-proxy
              If the environment variable ‘http_proxy’ has been set, use its value to access HTTP
              servers.  If on Windows the option is used but the environment variable is not set,
              the proxy settings are taken from the system.

       --http-proxy host[:port]
              Use host and port to access HTTP servers.  The use of  this  option  overrides  the
              environment  variable  ‘http_proxy’  regardless whether --honor-http-proxy has been
              set.

       --ldap-proxy host[:port]
              Use host and port to connect to  LDAP  servers.   If  port  is  omitted,  port  389
              (standard LDAP port) is used.  This overrides any specified host and port part in a
              LDAP URL and will also be used if host and port have been omitted from the URL.

       --only-ldap-proxy
              Never use anything else but the  LDAP  "proxy"  as  configured  with  --ldap-proxy.
              Usually  dirmngr  tries to use other configured LDAP server if the connection using
              the "proxy" failed.

       --ldapserverlist-file file
              Read the list of LDAP servers to consult for CRLs and X.509 certificates from  file
              instead  of  the default per-user ldap server list file. The default value for file
              is ‘dirmngr_ldapservers.conf’.

              This server list file contains one LDAP server per line in the format

              hostname:port:username:password:base_dn:flags

              Lines starting with a  ‘#’ are comments.

              Note that as usual all strings entered are expected to be UTF-8 encoded.  Obviously
              this  will lead to problems if the password has originally been encoded as Latin-1.
              There is no other solution here than to put such a password in the binary  encoding
              into  the  file  (i.e.  non-ascii characters won't show up readable). ([The gpgconf
              tool might be helpful for frontends as it enables editing this  configuration  file
              using percent-escaped strings.])

       --ldapserver spec
              This  is  an  alternative way to specify LDAP servers for CRL and X.509 certificate
              retrieval.    If   this   option   is    used    the    servers    configured    in
              ‘dirmngr_ldapservers.conf’   (or  the  file  given  by  --ldapserverlist-file)  are
              cleared.  Note that ‘dirmngr_ldapservers.conf’  is  not  read  again  by  a  reload
              signal. However, --ldapserver options are read again.

              spec is either a proper LDAP URL or a colon delimited list of the form

              hostname:port:username:password:base_dn:flags:

              with an optional prefix of ldap: (but without the two slashes which would turn this
              into a proper LDAP URL).  flags is a list of one or more comma delimited keywords:

              plain  The default: Do not use a TLS secured connection at all; the default port is
                     389.

              starttls
                     Use STARTTLS to secure the connection; the default port is 389.

              ldaptls
                     Tunnel LDAP through a TLS connection; the default port is 636.

              ntds   On  Windows authenticate the LDAP connection using the Active Directory with
                     the current user.

              areconly
                     On Windows use only the A or AAAA record  when  resolving  the  LDAP  server
                     name.

       Note  that  in an URL style specification the scheme ldaps:// refers to STARTTLS and _not_
       to LDAP-over-TLS.

       --ldaptimeout secs
              Specify the number of seconds to wait for an LDAP query  before  timing  out.   The
              default are 15 seconds.  0 will never timeout.

       --add-servers
              This option makes dirmngr add any servers it discovers when validating certificates
              against CRLs to the internal list of servers to consult for certificates and  CRLs.
              This option should in general not be used.

              This  option  might  be useful when trying to validate a certificate that has a CRL
              distribution point that points to a server  that  is  not  already  listed  in  the
              ldapserverlist.  Dirmngr will always go to this server and try to download the CRL,
              but chances are high that the certificate used to sign the CRL is  located  on  the
              same  server.  So if dirmngr doesn't add that new server to list, it will often not
              be able to verify the signature of the CRL unless the --add-servers option is used.

              Caveat emptor: Using this option may  enable  denial-of-service  attacks  and  leak
              search  requests  to  unknown third parties.  This is because arbitrary servers are
              added to the internal list of LDAP servers which in turn is used for all unspecific
              LDAP queries as well as a fallback for queries which did not return a result.

       --allow-ocsp
              This option enables OCSP support if requested by the client.

              OCSP  requests  are rejected by default because they may violate the privacy of the
              user; for example it is possible to track the time when a user is reading a mail.

       --ocsp-responder url
              Use url as  the  default  OCSP  Responder  if  the  certificate  does  not  contain
              information about an assigned responder.  Note, that --ocsp-signer must also be set
              to a valid certificate.

       --ocsp-signer fpr|file
              Use the certificate with the fingerprint fpr to check the responses of the  default
              OCSP  Responder.   Alternatively a filename can be given in which case the response
              is expected to be signed by one of the certificates described in  that  file.   Any
              argument  which  contains  a  slash,  dot or tilde is considered a filename.  Usual
              filename expansion takes place: A tilde  at  the  start  followed  by  a  slash  is
              replaced  by the content of ‘HOME’, no slash at start describes a relative filename
              which will be searched at the home directory.   To  make  sure  that  the  file  is
              searched  in  the  home  directory, either prepend the name with "./" or use a name
              which contains a dot.

              If a response has been signed by a certificate described by these  fingerprints  no
              further check upon the validity of this certificate is done.

              The  format  of the FILE is a list of SHA-1 fingerprint, one per line with optional
              colons between the bytes.  Empty lines and  lines  prefix  with  a  hash  mark  are
              ignored.

       --ocsp-max-clock-skew n
              The  number  of  seconds  a skew between the OCSP responder and them local clock is
              accepted.  Default is 600 (10 minutes).

       --ocsp-max-period n
              Seconds a response is at maximum considered valid  after  the  time  given  in  the
              thisUpdate field.  Default is 7776000 (90 days).

       --ocsp-current-period n
              The  number of seconds an OCSP response is considered valid after the time given in
              the NEXT_UPDATE datum.  Default is 10800 (3 hours).

       --max-replies n
              Do not return more that n items in one query.  The default is 10.

       --ignore-cert-extension oid
              Add oid to the list of ignored certificate extensions.  The oid is expected  to  be
              in  dotted  decimal  form,  like 2.5.29.3.  This option may be used more than once.
              Critical flagged certificate extensions matching one of the OIDs in  the  list  are
              treated  as if they are actually handled and thus the certificate won't be rejected
              due to an unknown critical extension.  Use this option with care because extensions
              are usually flagged as critical for a reason.

       --ignore-crl-extension oid
              Add oid to the list of ignored CRL extensions.  The oid is expected to be in dotted
              decimal form.  Critical flagged CRL extensions matching one of the OIDs in the list
              are  treated  as  if  they  are  actually handled and thus the certificate won't be
              rejected due to an unknown critical extension.  Use this option with  care  because
              extensions are usually flagged as critical for a reason.

       --ignore-cert fpr|file
              Entirely  ignore  certificates  with the fingerprint fpr.  As an alternative to the
              fingerprint a filename can be given in which case  all  certificates  described  in
              that  file  are  ignored.   Any  argument  which  contains a slash, dot or tilde is
              considered a filename.  Usual filename expansion takes place: A tilde at the  start
              followed  by  a  slash  is  replaced  by  the  content of ‘HOME’, no slash at start
              describes a relative filename which will be searched at  the  home  directory.   To
              make  sure that the file is searched in the home directory, either prepend the name
              with "./" or use a name which contains a dot.  The format of such a file is a  list
              of  SHA-1  fingerprint, one per line with optional colons between the bytes.  Empty
              lines and lines prefixed with a hash mark are ignored.

              This option is useful as a quick workaround to exclude  certain  certificates  from
              the system store.

       --hkp-cacert file
              Use  the  root  certificates  in file for verification of the TLS certificates used
              with hkps (keyserver access over TLS).  If the file is in PEM format  a  suffix  of
              .pem  is  expected  for  file.  This option may be given multiple times to add more
              root certificates.  Tilde expansion is supported.

              If no hkp-cacert directive is present, dirmngr will use the system CAs.

EXAMPLES

       Here is an example on how to show dirmngr's internal table of OpenPGP keyserver addresses.
       The output is intended for debugging purposes and not part of a defined API.

           gpg-connect-agent --dirmngr 'keyserver --hosttable' /bye

       To  inhibit  the  use of a particular host you have noticed in one of the keyserver pools,
       you may use

          gpg-connect-agent --dirmngr 'keyserver --dead pgpkeys.bnd.de' /bye

       The description of the keyserver command can be printed using

          gpg-connect-agent --dirmngr 'help keyserver' /bye

FILES

       Dirmngr makes use of several directories when running in daemon  mode:  There  are  a  few
       configuration files to control the operation of dirmngr.  By default they may all be found
       in the current home directory (see: [option --homedir]).

       dirmngr.conf
              This is the standard configuration file read by dirmngr on startup.  It may contain
              any valid long option; the leading two dashes may not be entered and the option may
              not be abbreviated.  This file is also read after a SIGHUP however not all  options
              will actually have an effect.  This default name may be changed on the command line
              (see: [option --options]).  You should backup this file.

       /etc/gnupg/trusted-certs
              This directory should be filled with certificates of Root CAs you are  trusting  in
              checking the CRLs and signing OCSP Responses.

              Usually these are the same certificates you use with the applications making use of
              dirmngr.  It is expected that each of these certificate files contain  exactly  one
              DER  encoded certificate in a file with the suffix ‘.crt’ or ‘.der’.  dirmngr reads
              those certificates on startup and when given a SIGHUP.  Certificates which are  not
              readable or do not make up a proper X.509 certificate are ignored; see the log file
              for details.

              Applications using dirmngr (e.g. gpgsm) can request these certificates to  complete
              a trust chain in the same way as with the extra-certs directory (see below).

              Note   that   for  OCSP  responses  the  certificate  specified  using  the  option
              --ocsp-signer is always considered valid to sign OCSP requests.

       /etc/gnupg/extra-certs
              This directory may contain extra certificates which are preloaded into the internal
              cache  on  startup.  Applications  using  dirmngr  (e.g.  gpgsm) can request cached
              certificates to complete a trust chain.  This is convenient in  cases  you  have  a
              couple  intermediate  CA  certificates  or  certificates  usually used to sign OCSP
              responses.  These certificates are first tried before going out to the net to  look
              for  them.  These certificates must also be DER encoded and suffixed with ‘.crt’ or
              ‘.der’.

       ~/.gnupg/crls.d
              This directory is used to store cached CRLs.  The ‘crls.d’ part will be created  by
              dirmngr  if  it  does not exists but you need to make sure that the upper directory
              exists.

       Several options control the use of trusted certificates for TLS  and  CRLs.   Here  is  an
       Overview on the use and origin of those Root CA certificates:

       System

              These System root certificates are used by:  FIXME

              The origin of the system provided certificates depends on the platform.  On Windows
              all certificates from the Windows System Stores ROOT and CA are used.

              On other platforms the certificates are read from the first file  found  form  this
              list:        ‘/etc/ssl/ca-bundle.pem’,        ‘/etc/ssl/certs/ca-certificates.crt’,
              ‘/etc/pki/tls/cert.pem’,                  ‘/usr/local/share/certs/ca-root-nss.crt’,
              ‘/etc/ssl/cert.pem’.

       GnuPG

              The  GnuPG specific certificates stored in the directory ‘/etc/gnupg/trusted-certs’
              are only used to validate CRLs.

       OpenPGP keyserver

              For accessing the OpenPGP keyservers the only certificates used are those set  with
              the configuration option hkp-cacert.

       OpenPGP keyserver pool

              This     is    usually    only    one    certificate    read    from    the    file
              ‘/usr/share/gnupg/gnupg/sks-keyservers.netCA.pem’.  If this certificate  exists  it
              is   used   to  access  the  special  keyservers  hkps.pool.sks-keyservers.net  (or
              ‘hkps://keys.gnupg.net’).

       Please note that gpgsm accepts Root CA certificates for its own purposes only if they  are
       listed  in  its  file  ‘trustlist.txt’.   dirmngr  does not make use of this list - except
       FIXME.

NOTES

       To be able to see diagnostics it is often useful to put at least the following lines  into
       the configuration file ‘~/gnupg/dirmngr.conf’:

         log-file ~/dirmngr.log
         verbose

       You  may  want  to  check the log file to see whether all desired root CA certificates are
       correctly loaded.

       To be able to perform OCSP requests you probably want to add the line:

         allow-ocsp

       To make sure that new options are read or that after  the  installation  of  a  new  GnuPG
       versions the right dirmngr version is running, you should kill an existing dirmngr so that
       a new instance is started as needed by the other components:

         gpgconf --kill dirmngr

       Direct interfaction with the dirmngr is possible by using the command

         gpg-connect-agent --dirmngr

       Enter HELP at the prompt to see a list of commands and enter HELP followed  by  a  command
       name to get help on that command.

SIGNALS

       A  running  dirmngr  may  be  controlled by signals, i.e. using the kill command to send a
       signal to the process.

       Here is a list of supported signals:

       SIGHUP This signal flushes all internally cached CRLs as well as any cached  certificates.
              Then  the  certificate  cache  is reinitialized as on startup.  Options are re-read
              from the configuration file.  Instead of sending this signal it is better to use
         gpgconf --reload dirmngr

       SIGTERM
              Shuts down the process but waits until all current requests are fulfilled.  If  the
              process  has received 3 of these signals and requests are still pending, a shutdown
              is forced.  You may also use
         gpgconf --kill dirmngr
       instead of this signal

       SIGINT Shuts down the process immediately.

       SIGUSR1
              This prints some caching statistics to the log file.

SEE ALSO

       gpgsm(1), dirmngr-client(1)

       The full documentation for this tool is maintained as a Texinfo manual.  If GnuPG and  the
       info program are properly installed at your site, the command

         info gnupg

       should give you access to the complete manual including a menu structure and an index.