Hello!
I have a very big problem when I tried to change group permission (sysadm_group) of the instance, that is:

before:
"
SYSADM group name (SYSADM_GROUP) = DB2GRP1
SYSCTRL group name (SYSCTRL_GROUP) =
SYSMAINT group name (SYSMAINT_GROUP) =
SYSMON group name (SYSMON_GROUP) =
"
after:
"
SYSADM group name (SYSADM_GROUP) = DB2SYSADM
SYSCTRL group name (SYSCTRL_GROUP) = DB2SYSCTRL
SYSMAINT group name (SYSMAINT_GROUP) = DB2SYSMAINT
SYSMON group name (SYSMON_GROUP) = DB2SYSMON
"
I write follow statements (as db2inst1 user):
update dbm cfg using sysadm_group db2sysadm
update dbm cfg using sysctrl_group db2sysctrl
update dbm cfg using sysmaint_group db2sysmaint
update dbm cfg using sysmon_group db2sysmon

then I add groups:
groupadd db2sysadm
ecc..
and I lanch in my home (db2inst1):
chown db2inst1.db2sysadm * -R

Now my client don't connect to database and I keep this message error:

SQL30082N Attempt to establish connection failed with security reason "24" ("USERNAME AND/OR PASSWORD INVALID"). SQLSTATE=08001

I really need your help..

Best regards
Fabio

Sorry!
I forgot to specify the environment:

Suse 64-bit, RAM 2GB with kernel parameters:

# Added for 64-bit DB2
kernel.sem=250 256000 32 1024
kernel.msgmni=1024
kernel.shmmax=1610612736
kernel.shmall=400000
kernel.shmmni=4096
#end additions for DB2

and DB2 Udb Enterprise Server 8.2.6 .

Thank you.
Fabio

What you forgot to specify are the most relevant details:
- what kind of client
- local or remote
- the exact command line when you are trying to connect

Ok, thank you!
I have these parameters in Database Manager Configuration:

"
Database manager authentication (AUTHENTICATION) = SERVER
Cataloging allowed without authority (CATALOG_NOAUTH) = NO
Trust all clients (TRUST_ALLCLNTS) = YES
Trusted client authentication (TRUST_CLNTAUTH) = CLIENT
Bypass federated authentication (FED_NOAUTH) = NO
"

and I can't connect with a remote client, also after resetting parameters (SYSADM_GROUP, SYSCTRL_GROUP, SYSMAINT_GROUP and SYSMON_GROUP) and privileges in the home path of the user instance with:
sudo chown db2inst1.db2grp1 * -R

I suspect that the problem is the previous command "chown db2inst1.db2sysadm * -R" ...can privileges break the layer between DB2 and OS authentication??

thank you very much!