+.SH "ENVIRONMENT VARIABLES"
+Several environment variables affect the operation of Kerberos-enabled
+programs. These include:
+.TP
+.B KRB5CCNAME
+Specifies the location of the credential cache, in the form
+\fITYPE\fP:\fIresidual\fP. If no type prefix is present, the
+\fBFILE\fP type is assumed and \fIresidual\fP is the pathname of the
+cache file. A collection of multiple caches may be used by specifying
+the \fBDIR\fP type and the pathname of a private directory (which must
+already exist). The default cache file is /tmp/krb5cc_\fIuid\fP where
+\fIuid\fP is the decimal user ID of the user.
+.TP
+.B KRB5_KTNAME
+Specifies the location of the keytab file, in the form
+\fITYPE\fP:\fIresidual\fP. If no type is present, the \fBFILE\fP type
+is assumed and \fIresidual\fP is the pathname of the keytab file. The
+default keytab file is /etc/krb5.keytab.
+.TP
+.B KRB5_CONFIG
+Specifies the location of the Kerberos configuration file. The
+default is /etc/krb5.conf.
+.TP
+.B KRB5_KDC_PROFILE
+Specifies the location of the KDC configuration file, which contains
+additional configuration directives for the Key Distribution Center
+daemon and associated programs. The default is
+/usr/local/var/krb5kdc/kdc.conf.
+.TP
+.B KRB5RCACHETYPE
+Specifies the default type of replay cache to use for servers. Valid
+types include "dfl" for the normal file type and "none" for no replay
+cache.
+.B KRB5RCACHEDIR
+Specifies the default directory for replay caches used by servers.
+The default is the value of the \fBTMPDIR\fP environment variable, or
+/var/tmp if \fBTMPDIR\fP is not set.
+.TP
+.B KRB5_TRACE
+Specifies a filename to write trace log output to. Trace logs can
+help illuminate decisions made internally by the Kerberos libraries.
+The default is not to write trace log output anywhere.