Archive for category Aix
AIX and user access denied
Posted by Lincoln Zuljewic Silva in Aix on May 19, 2010
AIX has a security feature named unsuccessful_login_count (/etc/security/lastlog) . It is an user account feature that count the number of unsuccessful login attempts and it works conjunction with the user's loginretries (/etc/security/user) attribute.
So, if you configure the loginretries=5, the user will not be able to log in after 5 retries. To enable the login again, you should reset the unsuccessful_login_count parameter by editing the file /etc/security/lastlog or with the following command:
# chsec -f /etc/security/lastlog -a unsuccessful_login_count=0 -s foobar
You can identify this problem by the following message in syslog:
May 19 15:42:41 aixbox auth|security:info sshd[7884888]: Login restricted for foobar: 3004-303 There have been too
many unsuccessful login attempts; please see \tthe system administrator.
Change user settings and password attributes in AIX
Posted by Lincoln Zuljewic Silva in Aix on May 11, 2010
To change some user and password settings in AIX, you should use the command "chuser". Follow some available parameters:
- loginretries -> number of login failures before lock the account.
- maxage -> maximum age of a password (in weeks)
- gecos -> general information about the user.
- groups
- home
- minlen -> minimum password length
- pgrp -> primary group
Example:
# chuser loginretries='0' maxage='0' gecos='User Foo Bar' groups='group1,group2,group3' home='/home/foobar' minlen='7' pgrp='groupX' <username>
Unlock user account in AIX
Posted by Lincoln Zuljewic Silva in Aix on May 11, 2010
To unlock an user account in AIX, you should use the following command:
# chuser account_locked='true' <username>
Lock user account in AIX
Posted by Lincoln Zuljewic Silva in Aix on May 11, 2010
To lock an user account in AIX, you should use the following command:
# chuser account_locked='false' <username>
Physical memory in AIX
Posted by Lincoln Zuljewic Silva in Aix on February 18, 2010
To check the amount of physical RAM that a AIX Server has, you can use the following commands:
# lsattr -El sys0 | grep realmem
realmem 16121856 Amount of usable physical memory in Kbytes
or
# lsattr -El mem0
goodsize 15744 Amount of usable physical memory in Mbytes False
size 15744 Total amount of physical memory in Mbytes False
or
# prtconf|grep "Memory Size"
Memory Size: 15744 MB Good Memory Size: 15744 MB
Disable file size limit in AIX
Posted by Lincoln Zuljewic Silva in Aix on December 4, 2009
By default, if you try do copy/create a file larger than 2Gb in AIX, you will get a “file too large” message. That happen because AIX have a default limit of 2Gb for files.
To disable (or increase) this limit, edit /etc/security/limits and change the parameter fsize to “-1” or whatever value you want.
You can change it in “default” to apply to all users or change it to a specific user.
Remember that the file system should be JFS2.
Creating an user on AIX
Posted by Lincoln Zuljewic Silva in Aix on December 1, 2009
Creating an user on AIX
On AIX, you can use the following commands to create an user
# mkuser pgrp='primary group' groups='other groups' home='home directory' shell='/usr/bin/ksh' gecos='GECOS' USERNAME
Forcing an user changing the password on AIX
Posted by Lincoln Zuljewic Silva in Aix on November 30, 2009
Forcing an user changing the password on AIX
On AIX, you can use the following commands to unlock na user and force it to change it’s password on first logon:
# pwdadm -f ADMCHG USER