KRB5KDC(8) MIT Kerberos KRB5KDC(8)

# [NAME](#NAME)

krb5kdc - Kerberos V5 KDC

# [SYNOPSIS](#SYNOPSIS)

**krb5kdc** \[**-x** *db\_args*] \[**-d** *dbname*] \[**-k** *keytype*] \[**-M** *mkeyname*] \[**-p** *portnum*] \[**-m**] \[**-r** *realm*] \[**-n**] \[**-w** *numworkers*] \[**-P** *pid\_file*] \[**-T** *time\_offset*]

# [DESCRIPTION](#DESCRIPTION)

krb5kdc is the Kerberos version 5 Authentication Service and Key Distribution Center (AS/KDC).

# [OPTIONS](#OPTIONS)

The **-r** *realm* option specifies the realm for which the server should provide service. This option may be specified multiple times to serve multiple realms. If no **-r** option is given, the default realm (as specified in *krb5.conf*) will be served.

The **-d** *dbname* option specifies the name under which the principal database can be found. This option does not apply to the LDAP database.

The **-k** *keytype* option specifies the key type of the master key to be entered manually as a password when **-m** is given; the default is **aes256-cts-hmac-sha1-96**.

The **-M** *mkeyname* option specifies the principal name for the master key in the database (usually **K/M** in the KDC's realm).

The **-m** option specifies that the master database password should be fetched from the keyboard rather than from a stash file.

The **-n** option specifies that the KDC does not put itself in the background and does not disassociate itself from the terminal.

The **-P** *pid\_file* option tells the KDC to write its PID into *pid\_file* after it starts up. This can be used to identify whether the KDC is still running and to allow init scripts to stop the correct process.

The **-p** *portnum* option specifies the default UDP and TCP port numbers which the KDC should listen on for Kerberos version 5 requests, as a comma-separated list. This value overrides the port numbers specified in the *\[kdcdefaults]* section of *kdc.conf*, but may be overridden by realm-specific values. If no value is given from any source, the default port is 88.

The **-w** *numworkers* option tells the KDC to fork *numworkers* processes to listen to the KDC ports and process requests in parallel. The top level KDC process (whose pid is recorded in the pid file if the **-P** option is also given) acts as a supervisor. The supervisor will relay SIGHUP signals to the worker subprocesses, and will terminate the worker subprocess if the it is itself terminated or if any other worker process exits.

The **-x** *db\_args* option specifies database-specific arguments. See *Database Options* in *kadmin* for supported arguments.

The **-T** *offset* option specifies a time offset, in seconds, which the KDC will operate under. It is intended only for testing purposes.

# [EXAMPLE](#EXAMPLE)

The KDC may service requests for multiple realms (maximum 32 realms). The realms are listed on the command line. Per-realm options that can be specified on the command line pertain for each realm that follows it and are superseded by subsequent definitions of the same option.

For example:

```
krb5kdc -p 2001 -r REALM1 -p 2002 -r REALM2 -r REALM3
```

specifies that the KDC listen on port 2001 for REALM1 and on port 2002 for REALM2 and REALM3. Additionally, per-realm parameters may be specified in the *kdc.conf* file. The location of this file may be specified by the **KRB5\_KDC\_PROFILE** environment variable. Per-realm parameters specified in this file take precedence over options specified on the command line. See the *kdc.conf* description for further details.

# [ENVIRONMENT](#ENVIRONMENT)

See *kerberos* for a description of Kerberos environment variables.

As of release 1.22, krb5kdc supports systemd socket activation via the LISTEN\_PID and LISTEN\_FDS environment variables. Sockets provided by the caller must correspond to configured listener addresses (via the **kdc\_listen** variable or equivalent) or they will be ignored. Any configured listener addresses that do not correspond to caller-provided sockets will be ignored if socket activation is used.

# [SEE ALSO](#SEE_ALSO)

*kdb5\_util*, *kdc.conf*, *krb5.conf*, *kdb5\_ldap\_util*, *kerberos*

# [AUTHOR](#AUTHOR)

MIT

# [COPYRIGHT](#COPYRIGHT)

1985-2026, MIT

1.22.2

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Document: krb5kdc(8) from krb5 1.22.2-r5 (Chainguard OS)
Source: https://github.com/krb5/krb5.git