The purpose is to create a Standard Operating Environment which can be installed through NIM, and offers all functionality as configured on 5.3:
- All default configuration and setup
- For example DNS, NTP, filesystems, additional software, etc.
- Tuning
- For example limitations, unnecessary software and services, etc.
- User Environment
- Profile and homedir configuration
- Security
- AIX security
- LDAP authentication on eDirectory
- Sudo
- Syslog
Although the paragraphs will refer to more necessary when necessary the overall document on which this article is based is AIX Post Install. That document was created on AIX 5.3 and gives a lot of background information. This document adds specific information for AIX 6.1, but does not copy the background information which is also valid for AIX 5.3. So, in conclusion, if you need more information the AIX Post Install is your best place to start.
Installation
The installation is performed through NIM and the version installed is:
6100-04-03-1009
which was released in February 2010. During the install I accepted all default settings.
Default Configuration
Change Root
- Change root's password by issuing the command 'passwd' on the commandline after login.
- Change root's account through smitty by issuing the command 'smitty users' on the commandline:
- Change / Show Characteristics of a User
- Select the root user
- Set root's home directory to /home/root
Note:
- You'll have to create the /home/root directory and set permissions.
- Because Root's home is initially set to / you might want to copy root's files to it's new home directory.
DNS
Setup DNS by editing the 'resolv.conf' configuration file:
# vi /etc/resolv.conf nameserver 10.10.10.100 nameserver 10.10.10.101 search intranet.company.nl company.local
Note:
- The search entry can have up to a maximum of 1024 characater strings for the DomainName variable.
- The first DomainName variable is interpreted as the default domain name.
- The DomainName variable is the name of a domain that should be included in the search list.
- The domain entry and search entry are mutually exclusive. If both entries are used, the one that appears last will override the other.
NTP
Timezone
Setup the timezone through 'smitty':
- System Environments
- Change / Show Date, Time, and Time Zone
- Change Time Zone Using System Defined Values
- Select your country (NL - Netherlands)
- Select your time zone name (Europe/Amsterdam - (GMT+01:00/GMT+02:00) Central Europe)
- Confirm
NTP Config
Setup NTP by editing the 'ntp.conf' configuration file:
# vi /etc/ntp.conf #broadcastclient driftfile /etc/ntp.drift tracefile /etc/ntp.trace server ntp.company.nl
Set the Time
# ntpdate ntp.company.nl 3 Mar 10:02:29 ntpdate[250036]: step time server 10.10.10.100 offset 0.975368 sec # ntpdate ntp.company.nl 3 Mar 10:02:39 ntpdate[250040]: adjust time server 10.10.10.100 offset 0.000045 sec
NTP Service
Configure the NTP service to start automatically through 'smitty xntpd':
- Start Using the xntpd Subsystem
- BOTH
Reboot
To completely setup time and related services correctly reboot since the timezone change requires one.
NFS
Add the company NFS share through 'smitty manfs'
- Network File System (NFS)
- Network File System (NFS)
- Add a File System for Mounting
- Pathname of mount point [/exports/install]
- Pathname of remote directory [/exports/install]
- Host where remote directory resides [fileserver.company.nl]
- Mount now, add entry to /etc/filesystems or both? [both]
- /etc/filesystems entry will mount the directory on system restart. [yes]
- Mode for this NFS file system [read-only]
- Transport protocol to use [udp]
- Allow execution of setuid and setgid programs in this file system? [no]
- Allow device access via this mount? [no]
Check
There is a new filesystem defined in /etc/filesystems:
/exports/install:
dev = "/exports/install"
vfs = nfs
nodename = fileserver.company.nl
mount = true
options = ro,bg,hard,intr,proto=udp,nodev,nosuid,sec=sys
account = false
This filesystem is already mounted:
# mount
node mounted mounted over vfs date options
-------- --------------- --------------- ------ ------------ ---------------
/dev/hd4 / jfs2 Mar 03 10:13 rw,log=/dev/hd8
/dev/hd2 /usr jfs2 Mar 03 10:13 rw,log=/dev/hd8
/dev/hd9var /var jfs2 Mar 03 10:13 rw,log=/dev/hd8
/dev/hd3 /tmp jfs2 Mar 03 10:13 rw,log=/dev/hd8
/dev/hd1 /home jfs2 Mar 03 10:14 rw,log=/dev/hd8
/dev/hd11admin /admin jfs2 Mar 03 10:14 rw,log=/dev/hd8
/proc /proc procfs Mar 03 10:14 rw
/dev/hd10opt /opt jfs2 Mar 03 10:14 rw,log=/dev/hd8
/dev/livedump /var/adm/ras/livedump jfs2 Mar 03 10:14 rw,log=/dev/hd8
fileserver.company.nl /exports/install /exports/install nfs3 Mar 03 10:32 ro,bg,hard,intr,proto=udp,nodev,nosuid,sec=sys
Filesystems
When AIX gets installed the filesystem gets a certain amount of space dependent on the size of the disk and what is installed:
# df -m Filesystem MB blocks Free %Used Iused %Iused Mounted on /dev/hd4 320.00 154.38 52% 12990 25% / /dev/hd2 2144.00 355.22 84% 39261 31% /usr /dev/hd9var 192.00 17.66 91% 6439 57% /var /dev/hd3 64.00 61.55 4% 24 1% /tmp /dev/hd1 32.00 31.62 2% 11 1% /home /dev/hd11admin 128.00 127.63 1% 5 1% /admin /proc - - - - - /proc /dev/hd10opt 96.00 12.57 87% 1886 37% /opt /dev/livedump 256.00 255.64 1% 4 1% /var/adm/ras/livedump
Change the size of the filesystems using the 'chfs' command:
# chfs -a size=2G / # chfs -a size=4G /usr # chfs -a size=1G /var # chfs -a size=1G /tmp # chfs -a size=512M /home # chfs -a size=10G /opt
Result:
# df -m Filesystem MB blocks Free %Used Iused %Iused Mounted on /dev/hd4 2048.00 1882.11 9% 12990 3% / /dev/hd2 4096.00 2306.92 44% 39261 7% /usr /dev/hd9var 1024.00 849.48 18% 6441 4% /var /dev/hd3 1024.00 1021.37 1% 24 1% /tmp /dev/hd1 512.00 511.55 1% 11 1% /home /dev/hd11admin 128.00 127.63 1% 5 1% /admin /proc - - - - - /proc /dev/hd10opt 10240.00 10155.02 1% 1886 1% /opt /dev/livedump 256.00 255.64 1% 4 1% /var/adm/ras/livedump
Additional Software
Download the latest rpms:
IBM AIX Toolbox for Linux Applications Information page
Actual FTP download site
Get SSH and SSL from the AIX installation and expansion DVDs.
IBM AIX Toolbox for Linux Applications Information page
Actual FTP download site
Get SSH and SSL from the AIX installation and expansion DVDs.
Install AIX Software
Install AIX software with 'smitty install_latest':
- enter dir with software
...... Installation Summary -------------------- Name Level Part Event Result ------------------------------------------------------------------------------- rpm.rte 3.0.5.51 USR APPLY SUCCESS rpm.rte 3.0.5.51 ROOT APPLY SUCCESS openssl.base 0.9.8.1100 USR APPLY SUCCESS openssl.base 0.9.8.1100 ROOT APPLY SUCCESS openssh.base.client 5.2.0.5300 USR APPLY SUCCESS openssh.base.server 5.2.0.5300 USR APPLY SUCCESS openssh.base.client 5.2.0.5300 ROOT APPLY SUCCESS openssh.base.server 5.2.0.5300 ROOT APPLY SUCCESS
Install RPMS
This is a selection of RPMS I like to install on an AIX system:
# rpm -iv *.rpm bash-3.2-1 gcc-4.2.0-3 gettext-0.10.40-8 less-382-1 lsof-4.61-3 sudo-1.6.9p15-2noldap tar-1.14-2 vim-common-6.3-1 vim-enhanced-6.3-1 vim-minimal-6.3-1 which-2.14-1
SSH and SSL Config
SSH must be configured so X11 forwarding works as well. In a later configuration stage root will be forbidden to logon remotely, but for now that is still allowed. Configuration includes two files: /etc/ssh/sshd_config and /etc/ssh/ssh_config:
bash-3.2# cat /etc/ssh/sshd_config | grep '^[A-z]' Protocol 2 PermitRootLogin yes IgnoreRhosts yes X11Forwarding yes X11DisplayOffset 10 X11UseLocalhost yes TCPKeepAlive yes XauthLocation /usr/bin/X11/xauth Banner /etc/secure_banner Subsystem sftp /usr/libexec/sftp-server
bash-3.2# cat /etc/ssh/ssh_config | grep '^[A-z]' ForwardX11 yes ConnectTimeout 30 Protocol 2
Restart the ssh daemon:
# /etc/rc.d/rc2.d/Ssshd stop # /etc/rc.d/rc2.d/Ssshd start
After restarting your session you can issue 'xclock' to see if it's working.
See CygWin - X op Windows to see how to setup your local Windows installation for X11 forwarding.
Note: Don't forget to create and place you secure_banner in /etc.
Oracle Requirements
Oracle has a few requirements when installed on an AIX box, and one of them is not installed by default: bos.adt.libm. The package can be installed using the NIM server:
bash-3.2# lslpp -l bos.adt.libm lslpp: Fileset bos.adt.libm not installed. bash-3.2# nimclient -l -L ms-soe6 ...... lpp_6100_04_03 lpp_source ... ... bash-3.2# nimclient -o allocate -a lpp_source=lpp_6100_04_03 bash-3.2# nimclient -l -c resources ms-soe6 lpp_6100_04_03 lpp_source bash-3.2# nimclient -o cust -a lpp_source=lpp_6100_04_03 -a filesets=bos.adt.libm ... ... bash-3.2# lslpp -l bos.adt.libm Fileset Level State Description ---------------------------------------------------------------------------- Path: /usr/lib/objrepos bos.adt.libm 6.1.4.0 APPLIED Base Application Development Math Library
See AIX NIM for more information on how to install software using a NIM server.
Tuning
AIX Limitations
For system stability reasons AIX has a few limitations which interfere (within our company) with production processes.
SWAP
By default, the swap space is defined as 512 MB which is a little bit low when oracle, websphere or any other demanding application is running.
Set the paging space to 4 GB for better performance:
Set the paging space to 4 GB for better performance:
bash-3.2# lsps -a Page Space Physical Volume Volume Group Size %Used Active Auto Type Chksum hd6 hdisk0 rootvg 512MB 2 yes yes lv 0 bash-3.2# chps -s 112 hd6 bash-3.2# lsps -a Page Space Physical Volume Volume Group Size %Used Active Auto Type Chksum hd6 hdisk0 rootvg 4096MB 1 yes yes lv 0
Large Files
By default no one on the system is allowed to work with large files to prevent the filesystems from becoming full too fast, but we need root to work with large files. To do so, adjust the /etc/security/limits and these lines in the root section:
root:
fsize = -1
data = -1
stack = -1
Network
By default, AIX waits 200 ms before sending the TCP acknowledgement. To disable this setting issue:
bash-3.2# no -p -o tcp_nodelayack=1 Setting tcp_nodelayack to 1 Setting tcp_nodelayack to 1 in nextboot file
In AIX Post Install are extended tests regarding AIX performance and more background information.
Memory
When running Oracle the memory is better adjusted to meet the demands Oracle can make:
bash-3.2# vmo -p -o minperm%=5 -o maxperm%=90 -o maxclient%=90 -o lru_file_repage=0 Setting minperm% to 5 in nextboot file Modification to restricted tunable maxperm%, confirmation required yes/no yes Setting maxperm% to 90 in nextboot file Modification to restricted tunable maxclient%, confirmation required yes/no yes Setting maxclient% to 90 in nextboot file Modification to restricted tunable lru_file_repage, confirmation required yes/no yes Setting lru_file_repage to 0 in nextboot file Setting minperm% to 5 Setting maxperm% to 90 Warning: a restricted tunable has been modified Setting maxclient% to 90 Warning: a restricted tunable has been modified Setting lru_file_repage to 0 Warning: a restricted tunable has been modified
The default settings are:
vmo -p -o minperm%=20 -o maxperm%=80 -o maxclient%=80 -o lru_file_repage=1
Unnecessary Software
Software that is unnecessary:
- Alternate Disk Installation:
- bos.alt_disk_install.boot_images
- bos.alt_disk_install.rte
- Cluster Systems Management:
- csm.client
- csm.core
- csm.deploy
- csm.diagnostics
- csm.dsh
- csm.gui.dcem
To remove these packages issue:
installp -u bos.alt_disk_install.boot_images bos.alt_disk_install.rte csm.client csm.core csm.deploy csm.diagnostics csm.dsh csm.gui.dcem
According to KPMG security
- AIX Security Hardening:
- bos.aixpert.cmds
- bos.aixpert.websm
- Reliable Scalable Cluster Technology (RSCT)
- rsct.core.gui
- rsct.core.lprm
- rsct.core.sensorrm
installp -u bos.aixpert.cmds bos.aixpert.websm rsct.core.gui rsct.core.lprm rsct.core.sensorrm
Unnecessary Services
For more information about the services see the AIX Services Documentation.
Unnecessary Inetd Subservers
Use these commands to turn all subservers off:
chsubserver -d -v ftp -p tcp chsubserver -d -v telnet -p tcp chsubserver -d -v shell -p tcp chsubserver -d -v kshell -p tcp chsubserver -d -v login -p tcp chsubserver -d -v klogin -p tcp chsubserver -d -v exec -p tcp chsubserver -d -v comsat -p udp chsubserver -d -v uucp -p tcp chsubserver -d -v bootps -p udp chsubserver -d -v finger -p tcp chsubserver -d -v systat -p tcp chsubserver -d -v netstat -p tcp chsubserver -d -v tftp -p udp chsubserver -d -v talk -p udp chsubserver -d -v ntalk -p udp chsubserver -d -v rquotad -p udp chsubserver -d -v rexd -p tcp chsubserver -d -v rstatd -p udp chsubserver -d -v rusersd -p udp chsubserver -d -v rwalld -p udp chsubserver -d -v sprayd -p udp chsubserver -d -v pcnfsd -p udp chsubserver -d -v echo -p tcp chsubserver -d -v echo -p udp chsubserver -d -v discard -p tcp chsubserver -d -v discard -p udp chsubserver -d -v chargen -p tcp chsubserver -d -v chargen -p udp chsubserver -d -v daytime -p tcp chsubserver -d -v daytime -p udp chsubserver -d -v time -p tcp chsubserver -d -v time -p udp chsubserver -d -v instsrv -p tcp chsubserver -d -v xmquery -p udp chsubserver -d -v imap2 -p tcp chsubserver -d -v pop3 -p tcp chsubserver -d -v wsmserver -p tcp
After disabling all subservers don't forget to refresh the inetd daemon:
refresh -s inetd
Unnecessary Subsystems
Use these commands to stop and disable subsystems that are automatically started by AIX but are not needed:
chrctcp -S -d inetd chrctcp -S -d snmpd chrctcp -S -d hostmibd chrctcp -S -d snmpmibd chrctcp -S -d aixmibd chrctcp -S -d writesrv chrctcp -S -d qdaemon
- inetd: nternet daemon
- snmpd: simple network management protocol
- snmpmibd: extends snmp possibilities
- hostmibd: extends snmp possibilities
- aixmibd: extends snmp possibilities
- writesrv: enables the ability to receive massages from users from a remote system
- qdaemon: printer queue daemon
Remove Services from Inittab
Inittab starts a few more services which can be removed from inittab using these commands:
rmitab piobe rmitab writesrv rmitab qdaemon rmitab naudio rmitab naudio2 rmitab xmdaily rmitab pconsole
- piobe: spooler backend
- naudio(2): configures pci audio devices
- xmdaily: collects data regarding performance information
- pconsole: system director console (web administration tool)
SLP DA
Since the introduction of AIX 6.1 TL 3 an extra service can be disabled. More information can be found in this pdf (page 16).
To disable this Systems Director Common Agent (which is like a SLP DA) follow these steps:
To disable this Systems Director Common Agent (which is like a SLP DA) follow these steps:
- Comment out these line in /etc/inittab:
#platform_agent:2:once:/usr/bin/startsrc -s platform_agent >/dev/null 2>&1 #cimservices:2:once:/usr/bin/startsrc -s cimsys >/dev/null 2>&1
- Also run these commands:
sudo /opt/ibm/director/agent/runtime/agent/bin/endpoint.sh stop The LWI Nonstop Profile was not running. sudo /opt/ibm/director/agent/runtime/nonstop/bin/installnonstop.sh -uninstallservice
User Environment
Profile
I used AIX Profile to setup the profile for all users.
Home Directory
I used AIX Home Directory to setup the automatic creation of home directories for users.
Security
AIX Security
Intruder Lockout
To prevent brute force account hacking enable intruder lockout. This can be done by editing '/etc/security/login.cfg':
default:
sak_enabled = false
logintimes =
logindisable = 4
logininterval = 60
loginreenable = 30
logindelay = 5
For more information about these settings please check this page.
Valid Shells
Add bash to the list of valid shells, which can be done in the same file, '/etc/security/login.cfg':
usw:
shells = /bin/sh,/bin/bsh,/bin/csh,/bin/ksh,/bin/tsh,/bin/ksh93,/usr/bin/sh,/usr/bin/bsh,/usr/bin/csh,/u
sr/bin/ksh,/usr/bin/tsh,/usr/bin/ksh93,/usr/bin/rksh,/usr/bin/rksh93,/usr/sbin/sliplogin,/usr/sbin/uucp/uucico,/usr/sbin
/snappd,/bin/bash,/usr/bin/bash
maxlogins = 32767
logintimeout = 60
maxroles = 8
auth_type = STD_AUTH
Default User Settings
Set the default options for new created users to a higher level of security, 'vi /etc/security/user':
default:
admin = false
login = false
su = false
daemon = true
rlogin = true
sugroups =
admgroups =
ttys = ALL
auth1 = SYSTEM
auth2 = NONE
tpath = nosak
umask = 022
expires = 0
SYSTEM = "compat"
logintimes =
pwdwarntime = 7
account_locked = false
loginretries = 3
histexpire = 26
histsize = 4
minage = 1
maxage = 13
maxexpired = -1
minalpha = 5
minother = 3
minlen = 8
mindiff = 1
maxrepeats = 2
dictionlist =
pwdchecks =
Root Login
Set, in the same file, that root is allowed to login, 'vi /etc/security/user':
root
login = true
Automatic Timeout
Set an automatic timeout for sessions of one hour, 'vi /etc/profile':
....... # Automatic logout, include in export line if uncommented TMOUT=3600 ... ... export LOGNAME MAIL MAILMSG TERM TMOUT ... ...
Sendmail Privacy
Edit the /etc/sendmail.cf file to minimize the information sendmail shows on connection:
# privacy flags O PrivacyOptions=goaway
See Sendmail Security Quick Fixes for more information about sendmail security.
Don't forget to restart sendmail afterwards.
LDAP
LDAP authentication has been setup as described in AIX LDAP authentication on eDirectory.
Sudo
Sudo security has been setup as described in Sudo.
Root
You now have to make the final changes to the root account. Since you now have sudo rights for LDAP users root should no longer be allowed to login, except in emergencies. So, make sure users are allowed to 'su' to root and that root is only allowed a local login. You can change that in 'smitty users':
- Change / Show Characteristics of a User
- Select root
- Another user can SU TO USER?
- Set from “false” to “true”.
- User can LOGIN REMOTELY(rsh,tn,rlogin)?
- Set from “true” to “false”.
Also, don't forget to change the '/etc/ssh/sshd_config' to make sure root is not allowed to log in over ssh as well:
PermitRootLogin no
Syslog
Syslog has been setup as described in SYSLOG.
