Pentesting, Network Security and System Administration: May 2013

Thursday, May 30, 2013

Ethernet Card and Link Information in Linux

Command to find out Ethernet card driver name

You can try any one of the following command to find out your Ethernet card driver:
#lspci | grep Ethernet
Output:
04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express
05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8169 PCI Gigabit Ethernet Controller (rev 10)
Subsystem: Realtek Semiconductor Co., Ltd. RTL8169/8110 Family PCI Gigabit Ethernet NIC
Or

# dmesg | grep 'Ethernet driver'

Output:

8139cp: 10/100 PCI Ethernet driver v1.2 (Mar 22, 2004)

Or search a file called /var/log/dmesg:

# grep 'Ethernet driver' /var/log/dmesg

Output:

8139too Fast Ethernet driver 0.9.27
8139cp: 10/100 PCI Ethernet driver v1.2 (Mar 22, 2004)

You can also get driver name from config file:

# grep eth0 /etc/modprobe.conf

Output:

alias eth0 8139too

# vi /etc/modprobe.conf

Search for eth0 string.

In above example 8139too is driver loaded for eth0. You can find out more information about this driver using modinfo command:

# modinfo 8139too

modinfo program to show information about a Linux Kernel module. You can also find out all loaded modules or drivers using lsmod command:

# lsmod | less

lsmod is a program to show the status of modules in the Linux Kernel.

Command to check Ethernet Link status

#mii-tool eth0
Output:eth0: negotiated 100baseTx-FD flow-control, link ok

Wednesday, May 29, 2013

Init Script to start Oracle Database 11g R2 automatically while reboot

[root@db01 ~]# vi /etc/oratab

# This file is used by ORACLE utilities. It is created by root.sh
# and updated by the Database Configuration Assistant when creating
# a database.

# A colon, ':', is used as the field terminator. A new line terminates
# the entry. Lines beginning with a pound sign, '#', are comments.
#
# Entries are of the form:
# $ORACLE_SID:$ORACLE_HOME:<N|Y>:
#
# The first and second fields are the system identifier and home
# directory of the database respectively. The third filed indicates
# to the dbstart utility that the database should , "Y", or should not,
# "N", be brought up at system boot time.
#
# Multiple entries with the same $ORACLE_SID are not allowed.
#
#
orcl:/opt/app/oracle/product/11.2.0/dbhome_1:Y #default N

[root@db01 ~]# vi /home/oracle/.bash_profile

# add your SID at the last line

export ORACLE_SID=orcl

Create init script for Oracle

[root@db01 ~]# vi /etc/rc.d/init.d/oracle

#!/bin/bash

# oracle: Start/Stop Oracle Database 11g R2
#
# chkconfig: 345 90 10
# description: The Oracle Database is an Object-Relational Database Management System.
#
# processname: oracle

. /etc/rc.d/init.d/functions

LOCKFILE=/var/lock/subsys/oracle
ORACLE_HOME=/opt/app/oracle/product/11.2.0/dbhome_1
ORACLE_USER=oracle

case "$1" in
'start')
   if [ -f $LOCKFILE ]; then
      echo $0 already running.
      exit 1
   fi
   echo -n $"Starting Oracle Database:"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/lsnrctl start"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/dbstart $ORACLE_HOME"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/emctl start dbconsole"
   touch $LOCKFILE
   ;;
'stop')
   if [ ! -f $LOCKFILE ]; then
      echo $0 already stopping.
      exit 1
   fi
   echo -n $"Stopping Oracle Database:"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/lsnrctl stop"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/dbshut"
   su - $ORACLE_USER -c "$ORACLE_HOME/bin/emctl stop dbconsole"
   rm -f $LOCKFILE
   ;;
'restart')
   $0 stop
   $0 start
   ;;
'status')
   if [ -f $LOCKFILE ]; then
      echo $0 started.
      else
      echo $0 stopped.
   fi
   ;;
*)
   echo "Usage: $0 [start|stop|status]"
   exit 1
esac

exit 0

[root@db01 ~]# chmod 755 /etc/rc.d/init.d/oracle
[root@db01 ~]# /etc/rc.d/init.d/oracle start/status

Starting Oracle Database:
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 12-JUL-2011 23:41:57

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Starting /opt/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.2.0.1.0 - Production
System parameter file is /opt/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Log messages written to /opt/app/oracle/diag/tnslsnr/db01/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=orcl.localhost)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=orcl.localhost)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date                12-JUL-2011 23:41:57
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File         /opt/app/oracle/diag/tnslsnr/db01/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=orcl)(PORT=1521)))
The listener supports no services
The command completed successfully
Processing Database instance "orcl": log file /opt/app/oracle/product/11.2.0/dbhome_1/startup.log
Oracle Enterprise Manager 11g Database Control Release 11.2.0.1.0
Copyright (c) 1996, 2009 Oracle Corporation.  All rights reserved.
https://orcl:1158/em/console/aboutApplication
Starting Oracle Enterprise Manager 11g Database Control ........ started.
------------------------------------------------------------------
Logs are generated in directory /opt/app/oracle/product/11.2.0/dbhome_1/db01.server.world_db01/sysman/log

[root@db01 ~]#chkconfig --add oracle
[root@db01 ~]#chkconfig oracle on

Enjoy!!!!

Setting Time Zone in CentOS 5

Check the current timezone
# cat /etc/sysconfig/clock
ZONE=”America/Toronto”
UTC=true
ARC=false
There are two ways to change the timezone on CentOS.

1. Set the timezone by running system-config-date command
Before running the system-config-date tool, I created a file named “timestamp” as timestamp.
# date > timestamp
Type the system-config-date command at the command line to start the time and date properties tool.
# system-config-date
I selected “America/Vancouver” and press “OK” to exit.
Use the following command to find which configuration files had been changed.
# find /etc –newer timestamp
/etc/sysconfig/clock
/etc/localtime

From the above output, I know /etc/sysconfig/clock and /etc/localtime had been changed. Open the file /etc/sysconfig/clock, I found the “ZONE” had been changed. And I found the /etc/localtime had the same size with the file “/usr/share/zoneinfo/America/Vancouver”.

2. Set the timezone using /etc/sysconfig/clock and /etc/localtime configuration files
Since I know which files affect the timezone, I can modify manually. Use “vi” to modify the file /etc/sysconfig/clock, and change the “Vancouver” back to “Toronto”. Then copy “/usr/share/zoneinfo/America/Toronto” to /etc/localtime or use symbolic link command as below.
# ln -sf /usr/share/zoneinfo/America/Toronto /etc/localtime

Write the current System Time to the Hardware Clock
After changed the timezone, don’t forget to check the date and time using the date command, and then write the current System Time to the Hardware Clock.
# hwclock —systohc

Display date and time according to timezone
You can use TZ environment variable to display date and time according to your timezone. For example, I can display the local time of Los Angeles as below.

$ export TZ=America/Los_Angeles
$ date

There are two clocks on Linux system, which one is the Hardware Clock and the other one is the System Time. The Hardware Clock keeps running after the system shutdowns. When a Linux system boots, the script /etc/rc.d/rc.sysinit will run the /sbin/hwclock program to set the System Time from the Hardware Clock. When you want to set the Hardware Clock, you should use the date command to set the System Time first, and then set the Hardware Clock to the current System Time with the command /sbin/hwclock –systohc.

Installation and Configuration of Oracle 11g R2 database in CentOS 5! (WORKED EXAMPLE)

Log into the CentOS-5 system as the root user.

For setting up the system to be used by Oracle there are a few prerequisites that must be checked and possibly changed by the root user. Log in as the root user and this document will tell you when it is time to switch from the root user to someone else.

How much memory

command: grep -i memtotal /proc/meminfo

results: should be at least 1GB

How much swap

command: grep -i swaptotal /proc/meminfo

results: should be 1.5 the size of memtotal if memtotal < 2GB

should be equal to memtotal if memtotal is between 2GB and 8GB

should be .75 the size of memtotal if memtotal > 8GB

What processor type

command: grep "model name" /proc/cpuinfo

results: informational

How much available RAM and swap

command: free

results: informational

How much shared memory available

command: df -k /dev/shm

results: informational

purpose: The shared memory should be sized to be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET for each Oracle instance on the computer.

How much disk space in /tmp

command: df -k /tmp

results: should have at least 400MB available

How much disk space for Oracle binaries

command: df -k

results: Depending on installation type you should have between 1.5GB and 3.5GB

Checking Software Requirements

What distribution and version of Linux is installed

command: cat /proc/version

results: Linux version 2.6.18-8.1.15.el5 (mockbuild@builder6.centos.org)

(gcc version 4.1.1 20070105 (Red Hat 4.1.1-52))

#1 SMP Mon Oct 22 08:32:04 EDT 2007

What version of the kernel is installed

command: uname -r

results: 2.6.18-8.1.15.el5

Are the following packages installed (assumes CentOS-5 and above distribution)

command:rpm -q binutils \

compat-libstdc++ \

elfutils-libelf \

elfutils-libelf-devel \

glibc \

glibc-common \

glibc-devel \

glibc-headers \

gcc \

gcc-c++ \

libaio-devel \

libaio \

libgcc \

libstdc++ \

make \

sysstat \

unixODBC \

unixODBC-devel

results: you will probably get quite a few packages that are not installed with a typical installation. You can investigate missing packages with the following command making sure you add/subtract from this list if necessary.

yum list available "compat*" \

"elfutils*" \

"glibc*" \

"gcc*" \

"libaio*" \

"sysstat*" \

"unixODBC*"

action : Our base installation left us needing to issue the following command to install missing packages.

yum -y install compat-libstdc++-296.i386 \

compat-libstdc++-33.i386 \

elfutils-libelf-devel.i386 \

glibc-devel.i386 \

glibc-headers.i386 \

gcc.i386 \

gcc-c++.i386 \

libaio-devel.i386 \

sysstat.i386 \

unixODBC.i386 \

unixODBC-devel.i386

Create Oracle user and group

Create groups oinstall & dba

command: /usr/sbin/groupadd oinstall

/usr/sbin/groupadd dba

Create the Oracle and change password

command: /usr/sbin/useradd -g oinstall -G dba -s /bin/bash oracle

/usr/bin/passwd oracle

Validate the nobody user exists

command: /usr/bin/id nobody

results: this user is almost always created on a base CentOS installation

action : if this user is not created use the following command to create

/usr/sbin/useradd nobody

Configuring kernel parameters

The following kernel parameters must be validated and possibly changed. Use the commands given below to view a particular kernel setting and then change if the setting is lower than the recommendation given in the following table.

You can make the changes by editing the /etc/sysctl.conf file and then rebooting the server. The following results are what we observed on our server and should not be expected on yours.

shmmni	4096
shmall	2097152
shmmax	2147483648
semmsl	250
semmns	32000
semopm	100
semmni	128
file-max	65536
ip_local_port_range	1024 - 65000
rmem_default	1048576
rmem_max	1048576
wmem_default	262144
wmem_max	262144

command: /sbin/sysctl -a | grep kernel.sem

results: kernel.sem = 250 32000 100 128

command: /sbin/sysctl -a | grep kernel.shm

results: kernel.shmmni = 4096

kernel.shmall = 268435456

kernel.shmmax = 4294967295

command: /sbin/sysctl -a | grep file-max

results: fs.file-max = 102440

command: /sbin/sysctl -a | grep ip_local_port_range

results: net.ipv4.ip_local_port_range = 32768 61000

command: /sbin/sysctl -a | grep rmem_default

results: net.core.rmem_default = 109568

command: /sbin/sysctl -a | grep rmem_max

results: net.core.rmem_max = 131071

command: /sbin/sysctl -a | grep wmem_default

results: net.core.wmem_default = 109568

command: /sbin/sysctl -a | grep wmem_max

results: net.core.wmem_max = 131071

sample /etc/sysctl.conf file. This is given as an example only and does not reflect the results obtained above by the /sbin/sysctl commands. Only add lines that are needed and do not change any values to be lower than the base installation might have assigned.

kernel.shmall = 2097152

kernel.shmmax = 2147483648

kernel.shmmni = 4096

kernel.sem = 250 32000 100 128

fs.file-max = 65536

net.ipv4.ip_local_port_range = 1024 65000

net.core.rmem_default = 4194304

net.core.rmem_max = 4194304

net.core.wmem_default = 262144

net.core.wmem_max = 262144

Setting shell limits for the Oracle user

Add the following lines to /etc/security/limits.conf

oracle soft nproc 2047

oracle hard nproc 16384

oracle soft nofile 1024

oracle hard nofile 65536

Add the following lines to /etc/pam.d/login

session required /lib/security/pam_limits.so

session required pam_limits.so

Add the following lines to /etc/profile

if [ $USER = "oracle" ]; then

if [ $SHELL = "/bin/ksh" ]; then

ulimit -p 16384

ulimit -n 65536

else

ulimit -u 16384 -n 65536

Creating Directories to Install the Oracle Software

Validate you have enough space on disk and choose a directory to install

command: df -k

results: pick a mount point that has enough space—we have chosen /opt for the our.

Create subdirectories and give permissions to the oracle user

The following directory used is common for Oracle installations. Note that we are creating all directories under /opt and that there are no other applications using /opt/app and below. This is very important as we are changing permissions with the following commands.

command: mkdir -p /opt/app/oracle/product/11.2.0

chown -R oracle:oinstall /opt/app

chmod -R 775 /opt/app

Switch to the oracle user

Up to know we have been doing everything as the root user. It is now time to switch to the oracle user to actually install the Oracle software.

command: su – oracle

Add the following line to $HOME/.bash_profile

umask 022

Execute oracle's bash_profile to use new setting

command: . ./.bash_profile

Make sure the oracle user is using an X Windows System

It is assumed you know how to set up an X Windows System as stated earlier in the document. However you need to issue following command as root user first.

#xhost + (to accept X server connection from any client)

And then please verify it is working by setting DISPLAY and issuing the xterm command and validating an X Terminal comes up as oracle user.

$export DISPLAY=<hostname>:0.0

$xterm

You may close the X Terminal if you wish.

Set Oracle environment for the installation

Issue the following commands to set/unset particular Oracle environments in preparation for the installation.

command: export ORACLE_BASE=/opt/app/oracle

export ORACLE_SID=orcl

unset ORACLE_HOME

unset TNS_ADMIN

Start Oracle Installer

Unzip software into /opt

$unzip linux_11gR2_database_1of2.zip linux_11gR2_database_2of2.zip

$cd /opt/database

$./runInstaller

From this point, Oracle will do a few minor checks on the operating system and then put up the Oracle Installation screen. Our particular configuration did not throw any errors at this point but it should be noted, as it can be helpful, that sometimes the Oracle installer will complain at this very early stage about various Linux system configurations. If this is the case you might be able to bypass them by adding an additional argument to the runInstaller command. Please only use this as a last resort to the normal installation path.

command: ./runInstaller -ignoreSysPrereqs

From this point on we will walk through each of the prompts one at a time to give you a simple feel for a full installation of the Oracle software.

Select installation method

This screen is very busy to say the least. We are not going to create any databases at this point as it is not required nor is it suggested to do at this point. We like to create databases separately through the Database Creation Assistant (DBCA) and not confuse the software installation process.

1. Choose basic installation

1. verify Oracle Base of '/opt/app/oracle'

2. verify Oracle Home of '/opt/app/oracle/product/11.2.0/db_1'

3. verify installation type of 'Enterprise Edition'

4. verify dba group of 'dba'

2. Un-check “Create Starter Database”

3. Un-check “Advanced Installation”

4. Click< NEXT>

Specify Inventory directory and credentials

1. verify path of inventory directory of '/opt/app/oraInventory'

2. verify group name for install of 'oinstall'

3. Click< NEXT>

Product-Specific Prerequisite Checks

This screen, the installer will verify the system environment and report on any issues it may find. If all goes well you will get the status of 'Succeeded' for every check. Scroll through and make sure nothing has failed or look at the status box at the bottom of the screen and verify you get the following:

'Check complete. The overall result of this check is: Passed'

1. verify all statuses

2. Click< NEXT>

Summary

This screen give a summary of the installation you are about to perform. It can be interesting to click and expand the products being installed to give you an idea of the what product and version is going to be installed.

1. validate 'Global Settings' for directories

2. validate 'Space Requirements'

3. Click< NEXT>

Install

This screen gives a status of what is being installed. If all system settings have been properly set and all packages been installed properly then this should proceed without error. The status bar gives some indication of what is being installed at a particular point and the amount of work to be performed. But as all status bars you never really know how long in the process it is.

1. Note the time it takes for specific products. If you notice one hanging or taking a long amount of time (greater than 10 minutes) you could have a condition that requires a pre-installation patch. Don't stop the installer yet but instead start looking for a bug / patch for the Oracle 11g installation process and the actual product being installed.

2. Execute Configuration scripts

1. open up a different terminal window

2. login as the root user

3. run /opt/app/oraInventory/orainstRoot.sh

4. run /opt/app/oracle/product/11.2.0/db_1/root.sh

1. accept default of /usr/local/bin

5. Click< OK>

3. Click< EXIT>

4. Click< YES>

Check listener.ora file has SID_LIST_LISTENER line added.

$cat $ORACLE_HOME/network/admin/listener.ora

# listener.ora Network Configuration File: /opt/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
# Generated by Oracle configuration tools.
LISTENER =
(DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    )
)
SID_LIST_LISTENER=
(SID_LIST=
    (SID_DESC=
      (GLOBAL_DBNAME=orcl)
      (ORACLE_HOME=/opt/app/oracle/product/11.2.0/dbhome_1)
      (SID_NAME=orcl))
      )
ADR_BASE_LISTENER = /opt/app/oracle

Cleanup

1. If you downloaded the software from the net you can now remove .zip file and the complete directory structure you unzipped it to. That particular command is not given here as it can be quite disastrous if executed from the wrong directory.

2. Add the following lines to oracle's $HOME/.bash_profile file. This will allow you to execute various Oracle binaries to create databases, configure network settings, and generally manage the Oracle database environment.

export ORACLE_HOME=/opt/app/oracle/product/11.2.0/db_1

export PATH=$ORACLE_HOME/bin:$PATH

Last Thing to Remember

You need to set time zone of OS acceptable by ORACLE 11g.

$export TZ=Asia/Singapore (any timezone specified in emdb.properties file)

$date

Follow this link for setting TimeZone in CentOS 5:
http://shishirceh.blogspot.com/2013/05/setting-time-zone-in-centos-5.html

Reload the agent and database control

$emctl reload agent

$emctl stop dbconsole

$emctl start dbconsole

Go to your web browser and type https://serverip:5500/em

and login as sys, sysman as sysdba.

Installation is complete

Congratulations on a successful installation of the Oracle software. This paper hopefully was also successful in its attempt to guide you down a more simplistic path—giving you the commands to execute and working past the minor hurdles encountered during installation. Obviously this paper can not predict all the issues that you may encounter but if you have a relatively current system with ample memory and disk space there is no reason not to believe your installation wouldn't run smoothly.

To create another instance of Database

$dbca

and follow instruction in screen.

$emctl status dbconsole

Init Script to automatically start Oracle Database during reboot

http://shishirceh.blogspot.com/2013/05/init-script-to-start-oracle-database.html