multihomed IP address

[Greg Hudson]

On 06/22/2015 06:53 AM, Gsandtner Michael wrote:
> We want to connect with ssh via kerberos. The host's name resolves to one IP address, but the IP address resolves to two names (this is a required DNS configuration):
> # nslookup vmlxsuche1test
> Name:   vmlxsuche1test.host.magwien.gv.at
> Address: 10.153.92.100
> 
> # nslookup 10.153.92.100
> 100.92.153.10.in-addr.arpa      name = vmlxsuche1test.host.magwien.gv.at.
> 100.92.153.10.in-addr.arpa      name = zktest.host.magwien.gv.at.
> 
> ssh sometimes work, sometimes does not (falls back to authentication method: password).
> In both cases the credential cache on the client looks equal (got a TGS for both names):

ssh GSSAPI krb5 userauth does not work well when there are multiple
possible results for hostname canonicalization.  For unfortunate
historical reasons, MIT krb5 defaults to reverse-resolving the IP
address when canonicalizing hostnames.

For this situation, I believe adding "rdns = false" to the [libdefaults]
section in krb5.conf should resolve the issue.