# MIT Kerberos Documentation

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# MIT Kerberos defaults

## General defaults

Description | Default | Environment
--- | --- | ---
keytab file | `FILE:/etc/krb5.keytab` | KRB5_KTNAME
Client keytab file | `FILE:/etc/krb5/user/%{euid}/client.keytab` | KRB5_CLIENT_KTNAME
Kerberos config file krb5.conf | `/etc/krb5.conf``:``/etc``/krb5.conf` | KRB5_CONFIG
KDC config file kdc.conf | `/etc``/krb5kdc``/kdc.conf` | KRB5_KDC_PROFILE
GSS mechanism config file | `/etc``/gss/mech` | GSS_MECH_CONFIG
KDC database path (DB2) | `/etc``/krb5kdc``/principal` |
Master key stash file | `/etc``/krb5kdc``/.k5.`realm |
Admin server ACL file kadm5.acl | `/etc``/krb5kdc``/kadm5.acl` |
OTP socket directory | `/run``/krb5kdc` |
Plugin base directory | `/usr/lib/x86_64-linux-gnu``/krb5/plugins` |
replay cache directory | `/var/tmp` | KRB5RCACHEDIR
Master key default enctype | `aes256-cts-hmac-sha1-96` |
Default keysalt list | `aes256-cts-hmac-sha1-96:normal aes128-cts-hmac-sha1-96:normal` |
Permitted enctypes | `aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96 aes256-cts-hmac-sha384-192 aes128-cts-hmac-sha256-128 des3-cbc-sha1 arcfour-hmac-md5 camellia256-cts-cmac camellia128-cts-cmac` |
KDC default port | 88 |
Admin server port | 749 |
Password change port | 464 |

## Replica KDC propagation defaults

This table shows defaults used by the kprop and kpropd programs.

Description | Default | Environment
--- | --- | ---
kprop database dump file | `/etc``/krb5kdc``/replica_datatrans` |
kpropd temporary dump file | `/etc``/krb5kdc``/from_master` |
kdb5_util location | `/usr/sbin``/kdb5_util` |
kprop location | `/usr/sbin``/kprop` |
kpropd ACL file | `/etc``/krb5kdc``/kpropd.acl` |
kprop port | 754 | KPROP_PORT

## Default paths for Unix-like systems

On Unix-like systems, some paths used by MIT krb5 depend on parameters chosen at build time. For a custom build, these paths default to subdirectories of `/usr/local`. When MIT krb5 is integrated into an operating system, the paths are generally chosen to match the operating system’s filesystem layout.

Description | Symbolic name | Custom build path | Typical OS path
--- | --- | --- | ---
User programs | BINDIR | `/usr/local/bin` | `/usr/bin`
Libraries and plugins | LIBDIR | `/usr/local/lib` | `/usr/lib`
Parent of KDC state dir | LOCALSTATEDIR | `/usr/local/var` | `/var`
Parent of KDC runtime dir | RUNSTATEDIR | `/usr/local/var/run` | `/run`
Administrative programs | SBINDIR | `/usr/local/sbin` | `/usr/sbin`
Alternate krb5.conf dir | SYSCONFDIR | `/usr/local/etc` | `/etc`
Default ccache name | DEFCCNAME | `FILE:/tmp/krb5cc_%{uid}` | `FILE:/tmp/krb5cc_%{uid}`
Default keytab name | DEFKTNAME | `FILE:/etc/krb5.keytab` | `FILE:/etc/krb5.keytab`

The default client keytab name (DEFCKTNAME) typically defaults to `FILE:/usr/local/var/krb5/user/%{euid}/client.keytab` for a custom build. A native build will typically use a path which will vary according to the operating system’s layout of `/var`.