When authenticating from a Windows 7 2.6.1 enterprise client to a MongoDB 2.4.9 enterprise instance using Kerberos, the connection will only succeed if the FQDN is used in the URL instead of the short host name. Clients on Linux seem unaffected by this problem.

Example 1 - Using FQDN in the URL and everything works;

C:\Apps\MongoDB\2.6.1\bin>mongo host10601.intranet.mydomain.com:27118/admin -
authenticationDatabase='$external' -authenticationMechanism=GSSAPI -username mclennad@INTRANET.MYDOMAIN.COM
MongoDB shell version: 2.6.1
connecting to: host10601.intranet.mydomain.com:27118/admin
>

Example 2 - Using short name and get a GSSAPI error;

C:\Apps\MongoDB\2.6.1\bin>mongo host10601:27118/admin -authenticationDatabase=
'$external' -authenticationMechanism=GSSAPI -username mclennad@INTRANET.MYDOMAIN.COM
MongoDB shell version: 2.6.1
connecting to: host10601:27118/admin
2014-05-08T18:00:31.602-0400 Error: 17 SASL(-1): generic failure: SSPI: InitializeSecurityContext: The specified target is unknown or unreachable
at src/mongo/shell/db.js:1210
exception: login failed

Example 3 - DNS lookup of short name showing that FQDN is available;
C:\Apps\MongoDB\2.6.1\bin>nslookup host10601
Server: host013.mydomain.com
Address: 10.X.X.X

Non-authoritative answer:
Name: host10601.intranet.mydomain.com
Address: 10.Y.Y.Y