add Setting up DNS

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@12948 ec53bebd-3082-4978-b11e-865c3cabbd6b
This commit is contained in:
Love Hörnquist Åstrand
2003-10-03 04:03:36 +00:00
parent 97d37d8057
commit b40d499bb7

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@@ -16,6 +16,7 @@
* Incremental propagation:: * Incremental propagation::
* Salting:: * Salting::
* Cross realm:: * Cross realm::
* Setting up DNS::
@end menu @end menu
A A
@@ -508,7 +509,7 @@ the cell appended to the password.
@end itemize @end itemize
@node Cross realm, , Salting, Setting up a realm @node Cross realm, Setting up DNS , Salting, Setting up a realm
@section Cross realm @section Cross realm
@cindex Cross realm @cindex Cross realm
@@ -572,3 +573,44 @@ May 3 14:10:54 May 3 23:55:54 host/hummel.it.su.se@@SU.SE
@end cartouche @end cartouche
@end example @end example
@node Setting up DNS, , Cross realm, Setting up a realm
@section Setting up DNS
@cindex Setting up DNS
If there is information about where to find the KDC or kadmind for a
realm in the @file{krb5.conf} for a realm, that information will be
preferred and DNS will not be queried.
Heimdal will try to use DNS to find the KDCs for a realm. First it
will try to find @code{SRV} resource record (RR) for the realm. If no
SRV RRs are found, it will fall back to looking for a @code{A} RR for
a machine named kerberos.REALM, and then kerberos-1.REALM, etc
Adding this information to DNS makes the client have less
configuration (in the common case, no configuration) and allows the
system administrator to change the number of KDCs and on what machines
they are running without caring about clients.
The backside of using DNS that the client might be fooled to use the
wrong server if someone fakes DNS replies/data, but storing the IP
addresses of the KDC on all the clients makes it very hard to change
the infrastructure.
Example of the configuration for the realm @code{EXAMPLE.COM},
@example
$ORIGIN example.com.
_kerberos._tcp SRV 10 1 88 kerberos.example.com.
_kerberos._udp SRV 10 1 88 kerberos.example.com.
_kerberos._tcp SRV 10 1 88 kerberos-1.example.com.
_kerberos._udp SRV 10 1 88 kerberos-1.example.com.
_kpasswd._udp SRV 10 1 464 kerberos.example.com.
_kerberos-adm._tcp SRV 10 1 749 kerberos.example.com.
@end example
More information about DNS SRV resource records can be found in
RFC-2782 (A DNS RR for specifying the location of services (DNS SRV)).