HELP!! "Checksum failed" & "Integrity check on decrypted field failed "

I hope this is a newbie question for you guys out there since I've been googling for a solution for days but no luck so far.

I am trying to learn JAAS programming and got started from a very simple example where a client authenticate to kerberos and send messages to a echo server. I am using kerberos from MIT and it's running on a linux box. "krb5.conf" is as following:

[libdefaults]

ticket_lifetime = 600

default_realm = AMAIL.COM

#default_tkt_enctypes = des-cbc-crc

#default_tgs_enctypes = des-cbc-crc

#permitted_enctypes = des-cbc-crc des-cbc-md5

[realms]

AMAIL.COM ={

kdc = amail1.amail.com:88

admin_server = amail1.amail.com:749

default_domain = amail.com

}

[domain_realm]

.amail.com = AMAIL.COM

amail.com = AMAIL.COM

[logging]

kdc = FILE:/var/log/krb5kdc.log

admin_server = FILE:/var/log/kadmin.log

default = FILE:/var/log/krb5lib.log

the configuration file for the echo server and client is as following:

GSSClient{

com.sun.security.auth.module.Krb5LoginModule required debug=true;

};

GSSServer{

com.sun.security.auth.module.Krb5LoginModule required

storeKey=true debug=true;

};

The problems is when I run the client programme, the server outputs :

"GSSException: Failure unspecified at GSS-API level (Mechanism level: Checksum failed)"

However, when I uncomment "#permitted_enctypes = des-cbc-crc des-cbc-md5 " in krb5.conf, the server outputs:

"GSSException: Failure unspecified at GSS-API level (Mechanism level: Integrity check on decrypted field failed (31))"

I can see that I authenticated to kerberos successfully but the server fails when exchanging tokens with the client. Do I need to do any configurations on the echo server side or even the client side( there's a krb5.ini file in the windows folder and I modified it to have the same content as krb5.conf and I found varies sites mentioned keytab files but I am using username and password to authenticate client and server to kerberos)? I've tried to run the server and client on both Java 1.5 and Java 1.6 but got the same errors. Following is the full output of the server:

Debug istrue storeKeytrue useTicketCachefalse useKeyTabfalse doNotPromptfalse ticketCache isnull isInitiatortrue KeyTab isnull refreshKrb5Config isfalse principal isnull tryFirstPass isfalse useFirstPass isfalse storePass isfalse clearPass isfalse

[Krb5LoginModule] user entered username: root

Using builtindefault etypesfor default_tkt_enctypes

default etypesfor default_tkt_enctypes: 3 1 23 16 17.

Acquire TGT using AS Exchange

Using builtindefault etypesfor default_tkt_enctypes

default etypesfor default_tkt_enctypes: 3 1 23 16 17.

>>> KrbAsReq calling createMessage

>>> KrbAsReq in createMessage

>>> KrbKdcReq send: kdc=10.10.10.1 UDP:88, timeout=30000, number of retries =3, #bytes=139

>>> KDCCommunication: kdc=10.10.10.1 UDP:88, timeout=30000,Attempt =1, #bytes=139

>>> KrbKdcReq send: #bytes read=492

>>> EType: sun.security.krb5.internal.crypto.DesCbcMd5EType

>>> KrbAsRep cons in KrbAsReq.getReply root

Using builtindefault etypesfor default_tkt_enctypes

default etypesfor default_tkt_enctypes: 3 1 23 16 17.

principal is root@AMAIL.COM

EncryptionKey: keyType=3 keyBytes (hex dump)=0000: FD 13 B5 83 FB 01 34 FB

EncryptionKey: keyType=1 keyBytes (hex dump)=0000: FD 13 B5 83 FB 01 34 FB

EncryptionKey: keyType=23 keyBytes (hex dump)=0000: 32 91 53 F5 60 EB 32 9C0E 1D EE A5 5E 88 A1 E9 2.S.`.2.....^...

EncryptionKey: keyType=16 keyBytes (hex dump)=0000: F8 3D E5 C2 C1 9D 2A 6752 68 70 54 D5 E9 D0 58 .=....*gRhpT...X

0010: 85 8F 5B BF F4 91 23 B9

EncryptionKey: keyType=17 keyBytes (hex dump)=0000: E6 96 AD 05 B0 43 07 2386 99 D6 DC 0E 7B 60 39 .....C.#......`9

Added server's keyKerberos Principal root@AMAIL.COMKey Version 0key EncryptionKey: keyType=3 keyBytes (hex dump)=

0000: FD 13 B5 83 FB 01 34 FB