Problem with Java (j2sdk1.4.2_03 on a Windows XP client) and

[Seema Malkani]

For any questions on Sun's implementation of Java GSS/Kerberos,
please communicate to us via java-security at sun.com alias.

For latest Java GSS/Kerberos features in J2SE 1.5.0, please refer to:
http://java.sun.com/j2se/1.5.0/docs/guide/security/jgss/jgss-tiger.html

For Java GSS/Kerberos features available since J2SE1.4.2, please refer to:
http://java.sun.com/j2se/1.4.2/docs/guide/security/jgss/jgss-features.html

I have already responded to you. Sending out the same to MIT alias for 
other folks.

You need to setup "udp_preference_limit" configuration parameter in the
Kerberos configuration file krb5.conf under [libdefaults] section, if 
you want
your application to use TCP. If not specified, Java Kerberos library 
will fallback
to TCP only if the Kerberos ticket request using UDP fails and the KDC 
returns
the error code KRB_ERR_RESPONSE_TOO_BIG.

*udp_preference_limit*
    When sending a message to the KDC, the library will try using TCP 
before UDP
    if the size of the message is above udp_preference_limit. If the 
message is
    smaller than udp_preference_limit, then UDP will be tried before TCP.

For e.g. you can set udp_preference_limit =1 to always use TCP.

Hope this helps.
Seema

Rouiller Claude wrote:

>It seems now that Krb5LoginModule from java works (with TCP as fallback, as
>Ram says), but kinit only works with UDP. kinit from Java 1.4.2 seems to
>suffer from a bug when it has to use TCP.
>
>Can anyone confirm (or deny)?
>Claude
>
>-----Original Message-----
>From: ram marti [mailto:r.marti at comcast.net] 
>Sent: Tuesday, June 01, 2004 9:24 PM
>To: kerberos at MIT.EDU
>Subject: Re: Problem with Java (j2sdk1.4.2_03 on a Windows XP client) and
>
>
>
>Not quite correct. In 1.4.2, TCP should be used as a fall back when the 
>message size is large and the error code KRB_ERR_RESPONSE_TOO_BIG is 
>returned.
>
>
>
>See:
>
>http://java.sun.com/j2se/1.4.2/docs/guide/security/jgss/jgss-features.html
>
>"Support TCP for Kerberos Key Distribution Center Transport
>
>Sun's implementation of Kerberos implements Kerberos version 5 according 
>to RFC 1510 and uses UDP transport for ticket requests. A new Internet 
>draft updates this RFC. One of the added features is required support 
>for TCP as a transport in addition to UDP. As a result, in cases where 
>Kerberos tickets exceed the UDP packet size limit, the KDC would return 
>an error code indicating that the request should be resent over TCP.
>
>In the current 1.4.2 release, Sun's implementation of Kerberos now 
>supports automatic fallback to TCP. Therefore, if the Kerberos ticket 
>request using UDP fails and the KDC returns the error code 
>KRB_ERR_RESPONSE_TOO_BIG, TCP is automatically the default transport.
>
>..."
>
>If the error  KRB_ERR_RESPONSE_TOO_BIG is returned, TCP will be used.
>
>Thanks
>                = Ram Marti
>
>
>Jeffrey Altman wrote:
>  
>
>>Apparently Java's Kerberos implementation does not
>>support using TCP connections to obtain Kerberos tickets.
>>This is required when using Windows 2003 Active Directory
>>as the KDC because the Kerberos tickets must include all
>>of the Windows ACL data.  The Kerberos tickets are therefore
>>larger then the maximum size of a UDP packet.
>>
>>Jeffrey Altman
>>
>>
>>Rouiller Claude wrote:
>>
>>    
>>
>>>When I start (java-) kinit I get the following output:
>>>
>>>C:\DEV\OioTutorial>java -Dsun.security.krb5.debug=true
>>>sun.security.krb5.internal.tools.Kinit sso_testuser
>>>Config name: c:\winnt\krb5.ini
>>>
>>>      
>>>
>>>>>>KinitOptions cache name is C:\Documents and
>>>>>>            
>>>>>>
>>>Settings\sso_testadmin\krb5cc_sso_testadmin
>>>Principal is sso_testuser at SSOTEST.RTC.CH
>>>Password for sso_testuser at SSOTEST.RTC.CH:123
>>>
>>>      
>>>
>>>>>>Kinit console input 123
>>>>>>Kinit realm name is SSOTEST.RTC.CH
>>>>>>Creating KrbAsReq
>>>>>>KrbKdcReq local addresses for pcc2079 are:
>>>>>>            
>>>>>>
>>>
>>>        pcc2079/159.29.193.35
>>>
>>>      
>>>
>>>>>>KrbAsReq salt is SSOTEST.RTC.CHsso_testuser
>>>>>>EType: sun.security.krb5.internal.crypto.DesCbcMd5EType
>>>>>>KrbAsReq calling createMessage
>>>>>>KrbAsReq in createMessage
>>>>>>KrbAsReq etypes are: 3 1
>>>>>>Kinit: sending as_req to realm SSOTEST.RTC.CH
>>>>>>KrbKdcReq send: kdc=rtcnt978.ssotest.rtc.ch UDP:88, timeout=30000,
>>>>>>            
>>>>>>
>>>number of retries =3, #bytes=251
>>>
>>>      
>>>
>>>>>>KDCCommunication: kdc=rtcnt978.ssotest.rtc.ch UDP:88,
>>>>>>            
>>>>>>
>>>timeout=30000,Attempt =1, #bytes=251
>>>
>>>      
>>>
>>>>>>KrbKdcReq send: #bytes read=100
>>>>>>KrbKdcReq send: #bytes read=100
>>>>>>reading response from kdc
>>>>>>KDCRep: init() encoding tag is 126 req type is 11
>>>>>>KRBError:
>>>>>>            
>>>>>>
>>>         sTime is Tue Jun 01 11:17:27 CEST 2004 1086081447000
>>>         suSec is 511665
>>>         error code is 52
>>>         error Message is Response too big for UDP, retry with TCP
>>>         realm is SSOTEST.RTC.CH
>>>         sname is krbtgt/SSOTEST.RTC.CH
>>>Exception in thread "main" java.lang.IllegalAccessError: tried to access
>>>class sun.security.krb5.KrbKdcReq from class
>>>sun.security.krb5.internal.tools.Kinit
>>>        at sun.security.krb5.internal.tools.Kinit.<init>(Unknown Source)
>>>        at sun.security.krb5.internal.tools.Kinit.main(Unknown Source)
>>>
>>>Do you have any idea why i get this exception?
>>>
>>>Thanks in advance
>>>Claude
>>>
>>>________________________________________________
>>>Kerberos mailing list           Kerberos at mit.edu
>>>https://mailman.mit.edu/mailman/listinfo/kerberos
>>>
>>>      
>>>
>
>________________________________________________
>Kerberos mailing list           Kerberos at mit.edu
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>________________________________________________
>Kerberos mailing list           Kerberos at mit.edu
>https://mailman.mit.edu/mailman/listinfo/kerberos
>  
>