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chown or chgrp command is used to change the ownership.

Syntax of chown: chown [-R] username:groupname file/directory

Syntax of chgrp: chgrp [-R] groupname file/directory

Whenever user creates the file or directory, the owner of that file/directory automatically will be that user and that user’s primary group name.

To change group owner ship

chgrp training /data Which set the Group Ownership to training

or

chown root.training /dataWhich set the user owner to root and group owner to training group.

Verify /data using: ls -ld /data

You will get: drwxr-xr-x 2 root training …………..

Do the following steps as:

1.vi /var/schedule

30 17 * * * /sbin/dump -0u /dev/st0 /dev/hda7

2.crontab /var/schedule

3.service crond restart

We can add the cron schedule either by specifying the scripts path on /etc/crontab file or by creating on text file on crontab pattern.

cron helps to schedule on recurring events. Pattern of cron is:

MinuteHourDay of MonthMonthDay of WeekCommands

0-590-231-311-120-7 where 0 and 7 means Sunday.

Note * means every. To execute the command on every two minutes */2.

Do the following steps as:

Login as a root user

cat >schedule.txt

30 05 * * * /bin/echo “Hello”

3. crontab –u david schedule.txt

4. service crond restart

The cron system is essentially a smart alarm clock. When the alarm sounds, Linux runs the commands of your choice automatically. You can set the alarm clock to run at all sorts of regular time intervals. Alternatively, the at system allows you to run the command of your choice once, at a specified time in the future.

Red Hat configured the cron daemon, crond. By default, it checks a series of directories for jobs to run, every minute of every hour of every day. The crond checks the /var/spool/cron directory for jobs by user. It also checks for scheduled jobs for the computer under /etc/crontab and in the /etc/cron.d directory.

Here is the format of a line in crontab. Each of these columns is explained in more detail:

#minute, hour, day of month, month, day of week, command

*        *     *             *      *            command

Entries in a crontab Command Line

Field

Value

Minute

0-59

Hour

Based on a 24-hour clock; for example, 23 = 11 p.m.

Day of month

1-31

Month

1-12, or jan, feb, mar, etc.

Day of week

0-7; where 0 and 7 are both Sunday; or sun, mon, tue, etc.

Command

The command you want to run

Do the following steps as:

rpm -ivh ftp://server1.example.com/pub/kernel-hugemem-*

2. vi /etc/grub.conf

Set the default to new kernel

default=0

Example of /etc/grub.conf

default=0

timeout=5

splashimage=(hd0,0)/grub/splash.xpm.gz

hiddenmenu

title Red Hat Enterprise Linux ES (2.6.9-5.ELhugemem)

root (hd0,0)

kernel /vmlinuz-2.6.9-5.ELhugemem ro root=LABEL=/1 rhgb quiet

initrd /initrd-2.6.9-5.ELhugemem.img

title Red Hat Enterprise Linux ES (2.6.9-5.EL)

root (hd0,0)

kernel /vmlinuz-2.6.9-5.EL ro root=LABEL=/1 rhgb quiet

initrd /initrd-2.6.9-5.EL.img

rpm command is used to install, update and remove the rpm package. -ivh option is install, verbose, and display the hash mark.

Do the following steps as:

1.vi /etc/cron.allow

root

or

vi /etc/cron.deny

Write all user name to deny.

/etc/cron.allow, /etc/cron.deny file is used to control users to allow or deny. If /etc/cron.allow file is created only that users are allowed to run cron schedule. Another way to deny to users is /etc/cron.deny write all user name on single line.

Do the following steps as:

vi /etc/auto.master

/mnt/etc/auto.misc--timeout=50

vi /etc/auto.misc

data-rw,soft,intrserver1.example.com:/data

service autofs restart

chkconfig autofs on

When you mount the other filesystem, you should unmount the mounted filesystem, Automount feature of linux helps to mount at access time and after certain seconds, when user unaccess the mounted directory, automatically unmount the filesystem.

/etc/auto.master is the master configuration file for autofs service. When you startthe service, it reads the mount point as defined in /etc/auto.master.

Note: Examiner will provide you the Installation startup CD. And here mentioned size may vary see on the exam paper.

1.Insert the CD on CD-ROM and start the system.

2.In Boot: Prompt typelinux askmethod

3. It will display the Language, keyboard selection.

4. It will ask you for the installation method.

5. Select the HTTP from the list

6. It will ask the IP Address, Net mask, Gateway and Name Server. Select Use

Dynamic IP Configuration: because DHCP Server will be configured in your exam lab.

7. It will ask for the Web site name and Redhat Enterprise Linux Directory.

Specify the HTTP Server: 192.168.0.254

Directory: rhel4Because Default Directory for http is /var/www/html

8. After Connecting to the HTTP Server Installation start. Go upto the partition screen by selecting the different Options.

9. Create the partition According to the Question because Size and what-what partition should you create at installation time is specified in your question

10. Then select the MBR Options, time zone and go upto package selections.

It is another Most Important Time of installation. Due to the time limit, you should be

care about the installation packages. At Exam time you these packages are enough.

X-Window System

GNOME Desktop

(these two packages are generally not required)

Administration Tools.

System Tools

Windows File Server

FTP Servers

Mail Servers

Web Servers

Network Servers

Editors

Text Based Internet

Server Configuration Tools

Printing Supports

When installation will complete, your system will reboot. Jump for another Question.

IPP( Internet Printing Protocol), allows administrator to manage printer through browser so CUPS is called Internet Printing Protocol based on HTTP. We can Install the printer either through: system-confing-printer tool or through Browser.

1.Open the browser and Type on address: http://localhost:631CUPS (Common Unix Printing System) used the IPP protocol. CUPS use the 631 port.

2.Click on Manage Printer.

3.Click on Add Printer.

4.Type Printer name, Location, Description.

5.Select Device for bb. (Select IPP).

6.Device URL: ipp://192.168.0.254/ipp/ queue nameSame printer name of shared printer.

7.Select Model/Driver RAW printer.

8.service cups restart

Do the following steps as:

useradd eric

passwd eric

vi /etc/passwd

eric:x:505:505::/home/eric:/sbin/nologin

Which shell or program should start at login time is specified in /etc/passwd file. By default Redhat Enterprise Linux assigns the /bin/bash shell to the users. To deny the interactive login, you should write /sbin/nologin or /bin/false instead of login shell.

Do the following steps as:

1.chmod g+s /data

2.Verify using: ls -ld /data

Permission should be like:

drwxrws--- 2 root sysadmin 4096 Mar 16 18:08 /data

If SGID bit is set on directory then who every users creates the files on directory group owner automatically the owner of parent directory.

To set the SGID bit: chmod g+s directory

To Remove the SGID bit: chmod g-s directory

Do the following steps as:

groupadd training

To create a group we use the groupadd command.

Verify from: cat /etc/group whether group added or not?

Do the following steps as:

1.chmod 770 /data

2.Verify using : ls –ld /data

Preview should be like:

drwxrwx--- 2 root sysadmin 4096 Mar 16 18:08 /data

To change the permission on directory we use the chmod command. According to the question that only the owner user (root) and group member (sysadmin) can fully access the directory so: chmod 770 /data

Do the following steps as:

vi /etc/auto.master

/mnt/etc/auto.misc--timeout=50

vi /etc/auto.misc

data-rw,soft,intrserver1.example.com:/data

service autofs restart

chkconfig autofs on

When you mount the other filesystem, you should unmount the mounted filesystem, Automount feature of linux helps to mount at access time and after certain seconds, when user unaccess the mounted directory, automatically unmount the filesystem.

/etc/auto.master is the master configuration file for autofs service. When you start the service, it reads the mount point as defined in /etc/auto.master.

chown or chgrp command is used to change the ownership.

Syntax of chown: chown [-R] username:groupname file/directory

Syntax of chgrp: chgrp [-R] groupname file/directory

Whenever user creates the file or directory, the owner of that file/directory automatically will be that user and that user’s primary group name.

To change group owner ship

chgrp training /data Which set the Group Ownership to training

or

chown root.training /dataWhich set the user owner to root and group owner to training group.

Verify /data using: ls -ld /data

You will get: drwxr-xr-x 2 root training …………..

Do the following steps as:

Login as a root user

cat >schedule.txt

30 05 * * * /bin/echo “Hello”

3. crontab –u david schedule.txt

4. service crond restart

The cron system is essentially a smart alarm clock. When the alarm sounds, Linux runs the commands of your choice automatically. You can set the alarm clock to run at all sorts of regular time intervals. Alternatively, the at system allows you to run the command of your choice once, at a specified time in the future.

Red Hat configured the cron daemon, crond. By default, it checks a series of directories for jobs to run, every minute of every hour of every day. The crond checks the /var/spool/cron directory for jobs by user. It also checks for scheduled jobs for the computer under /etc/crontab and in the /etc/cron.d directory.

Here is the format of a line in crontab. Each of these columns is explained in more detail:

#minute, hour, day of month, month, day of week, command

*        *     *             *      *            command

Entries in a crontab Command Line

Field

Value

Minute

0-59

Hour

Based on a 24-hour clock; for example, 23 = 11 p.m.

Day of month

1-31

Month

1-12, or jan, feb, mar, etc.

Day of week

0-7; where 0 and 7 are both Sunday; or sun, mon, tue, etc.

Command

The command you want to run

Do the following steps as:

1.chgrp sysuser /archive

2.Verify using ls -ld /archive command. You should get like

drwxr-x--- 2 root sysadmin 4096 Mar 16 17:59 /archive

chgrp command is used to change the group ownership of particular files or directory.

Another way you can use the chown command.

chown root:sysuser /archive

Do the following steps as:

1.chgrp sysadmin /data

2.Verify using ls -ld /data command. You should get like

drwxr-x--- 2 root sysadmin 4096 Mar 16 17:59 /data

chgrp command is used to change the group ownership of particular files or directory.

Another way you can use the chown command.

chown root:sysadmin /data

Note: Examiner will provide you the Installation startup CD. And here mentioned size may vary see on the exam paper.

1.Insert the CD on CD-ROM and start the system.

2.In Boot: Prompt typelinux askmethod

3. It will display the Language, keyboard selection.

4. It will ask you for the installation method.

5. Select the HTTP from the list

6. It will ask the IP Address, Net mask, Gateway and Name Server. Select Use

Dynamic IP Configuration: because DHCP Server will be configured in your exam lab.

7. It will ask for the Web site name and Redhat Enterprise Linux Directory.

Specify the HTTP Server: 192.168.0.254

Directory: rhel5Because Default Directory for http is /var/www/html

8. After Connecting to the HTTP Server Installation start. Go upto the partition screen by selecting the different Options.

9. Create the partition According to the Question because Size and what-what partition should you create at installation time is specified in your question

10. Then select the MBR Options, time zone and go upto package selections.

It is another Most Important Time of installation. Due to the time limit, you should be

care about the installation packages. At Exam time you these packages are enough.

X-Window System

GNOME Desktop

(these two packages are generally not required)

Administration Tools.

System Tools

Windows File Server

FTP Servers

Mail Servers

Web Servers

Network Servers

Editors

Text Based Internet

Server Configuration Tools

Printing Supports

When installation will complete, your system will reboot. Jump for another Question.

Do the following steps as:

1.vi /etc/dhcpd.conf

ddns-update-style none;

option routers 192.168.0.1;

option domain-name “example.com”;

option domain-name-servers 192.168.0.254;

default-lease-time 21600;

max-lease-time 43200;

subnet 192.168.0.0 netmask 255.255.255.0

{

range 192.168.0.1 192.168.0.254;

host dns1 {

hardware ethernet 00:50:FC:98:8D:00;

fixed-address 192.168.0.254;

}

host dns2 {

hardware ethernet 00:50:FC:98:8C:00;

fixed-address 192.168.0.253;

}

}

/etc/dhcpd.conf file is used to configure the DHCP. Some global options i.e Gateway, domainname, DNS server specified using option keyword. To assign as static ip from dhcp server, required the mac address of interface.

2.service dhcpd start | restart

Do the following steps as:

1.vi /etc/security/time.conf

login;*;user15|user16;Sa0000-2400

2.vi /etc/pam.d/login

accountrequiredpam_time.so

For Time based authentication, we should configured in /etc/security/time.conf

Syntax of /etc/security/time.conf

services;ttys;users;times

services

is a logic list of PAM service names that the rule applies to.

ttys

is a logic list of terminal names that this rule applies to.

users

is a logic list of users to whom this rule applies.

times

the format here is a logic list of day/time-range entries the days are specified by a sequence of two character entries, MoTuSa for example is Monday Tuesday and Saturday. Note that repeated days are unset MoMo = no day, and MoWk = all weekdays bar Monday. The two character combinations accepted are

Mo Tu We Th Fr Sa Su Wk Wd Al

the last two being week-end days and all 7 days of the week respectively. As a final example, AlFr means all days except Friday.

pam_time modules checks the file /etc/security/time.conf for authentication. So, we should call the pam_time modules in /etc/pam.d/login.

Do the following steps as:

1.vi /etc/dhcpd.conf

ddns-update-style none;

option routers 192.168.0.1;

option domain-name “example.com”;

option domain-name-servers 192.168.0.254;

default-lease-time 21600;

max-lease-time 43200;

subnet 192.168.0.0 netmask 255.255.255.0

{

range 192.168.0.10 192.168.0.50;

}

/etc/dhcpd.conf file is used to configure the DHCP. Some global options i.e Gateway, domainname, DNS server specified using option keyword.

service dhcpd start | restart

Do the following steps as:

1.vi /etc/samba/smb.conf

[global]

netbios name=station?

workgroup=station?

security=user

smb passwd file=/etc/samba/smbpasswd

encrypt passwords=yes

hosts allow= .example.com

[data]

path=/data

public=no

writable=no

browsable=yes

2.smbpasswd -a eric

3.service smb start

4.chkconfig smb on

/etc/samba/smb.conf. There are some pre-defined section, i. globaluse to define the global options, ii. Printersuse to share the printers, iii. homesuse the share the user’s home directory.

Security=uservalidation by samba username and password. May be there are other users also. To allow certain share to certain user we should use valid users option.

smbpasswdHelps to change user’s smb password. –a option specifies that the username following should be added to the local smbpasswd file.

Do the following steps as:

1.ftp ftp://server1.example.com

2.Login as an anonymous and download the file.

3.Copy the file in /var/www/html if you downloaded in another location.

4.service httpd restart

5.Test using links: links http://station?.example.com

Note: In examination Lab DNS will configure for every stations.

Do the following steps as:

1.vi /etc/samba/smb.conf

[global]

netbios name=station?

workgroup = mygroup

server string=Share from Linux Server

security=user

smb passwd file=/etc/samba/smbpasswd

encrypt passwords=yes

[data]

path=/data

writable=no

public=no

browsable=yes

write list= user1 user2

2.smbpasswd –a user1

3.smbpasswd –a user2

……..

4.service smb start | restart

5.chkconfig smb on

Samba servers helps to share the data between linux and windows. Configuration file is /etc/samba/smb.conf. There are some pre-defined section, i. globaluse to define the global options, ii. Printersuse to share the printers, iii. homesuse the share the user’s home directory.

Security=uservalidation by samba username and password. May be there are other users also. To allow certain share to certain user we should use valid users option.

smbpasswdHelps to change user’s smb password. –a option specifies that the username following should be added to the local smbpasswd file.

If any valid users option is not specified, then all samba users can access the shared data. By Default shared permission is on writable=no means read only sharing. Write list option is used to allow write access on shared directory to certain users or group members.

Do the following steps as:

1.vi /etc/aliases

john:jane

2.newaliases

We can redirect the mail of one user to another user using /etc/aliases file. In example all mail of john goes to jane user. When you configure this line mail automatically goes to jane’s mail spooling directory.

Do the following steps as:

1.vi /etc/vsftpd/vsftpd.conf

anonymous_enable=no

2.service vsftpd restart

/etc/vsftpd/vsftpd.conf file is used to allow or deny to anonymous or real user. To allow anonymous anonymous_enable=yes should be there. Sample configuration is like.

# Allow anonymous FTP? (Beware - allowed by default if you comment this out).

anonymous_enable=YES

#

# Uncomment this to allow local users to log in.

local_enable=YES

#

# Uncomment this to enable any form of FTP write command.

write_enable=YES

#

# Default umask for local users is 077. You may wish to change this to 022,

# if your users expect that (022 is used by most other ftpd's)

local_umask=022

#

# Uncomment this to allow the anonymous FTP user to upload files. This only

# has an effect if the above global write enable is activated. Also, you will

# obviously need to create a directory writable by the FTP user.

#anon_upload_enable=YES

#

# Uncomment this if you want the anonymous FTP user to be able to create

# new directories.

#anon_mkdir_write_enable=YES

#

# Activate directory messages - messages given to remote users when they

# go into a certain directory.

dirmessage_enable=YES

#

# Activate logging of uploads/downloads.

xferlog_enable=YES

#

# Make sure PORT transfer connections originate from port 20 (ftp-data).

connect_from_port_20=YES

#

# If you want, you can arrange for uploaded anonymous files to be owned by

# a different user. Note! Using "root" for uploaded files is not

# recommended!

#chown_uploads=YES

#chown_username=whoever

#

# You may override where the log file goes if you like. The default is shown

# below.

#xferlog_file=/var/log/vsftpd.log

#

# If you want, you can have your log file in standard ftpd xferlog format

xferlog_std_format=YES

#

# You may change the default value for timing out an idle session.

#idle_session_timeout=600

#

# You may change the default value for timing out a data connection.

#data_connection_timeout=120

#

# It is recommended that you define on your system a unique user which the

# ftp server can use as a totally isolated and unprivileged user.

#nopriv_user=ftpsecure

#

# Enable this and the server will recognise asynchronous ABOR requests. Not

# recommended for security (the code is non-trivial). Not enabling it,

# however, may confuse older FTP clients.

#async_abor_enable=YES

#

# By default the server will pretend to allow ASCII mode but in fact ignore

# the request. Turn on the below options to have the server actually do ASCII

# mangling on files when in ASCII mode.

# Beware that turning on ascii_download_enable enables malicious remote parties

# to consume your I/O resources, by issuing the command "SIZE /big/file" in

# ASCII mode.

# These ASCII options are split into upload and download because you may wish

# to enable ASCII uploads (to prevent uploaded scripts etc. from breaking),

# without the DoS risk of SIZE and ASCII downloads. ASCII mangling should be

# on the client anyway..

#ascii_upload_enable=YES

#ascii_download_enable=YES

#

# You may fully customise the login banner string:

#ftpd_banner=Welcome to blah FTP service.

#

# You may specify a file of disallowed anonymous e-mail addresses. Apparently

# useful for combatting certain DoS attacks.

#deny_email_enable=YES

# (default follows)

#banned_email_file=/etc/vsftpd.banned_emails

#

# You may specify an explicit list of local users to chroot() to their home

# directory. If chroot_local_user is YES, then this list becomes a list of

# users to NOT chroot().

#chroot_list_enable=YES

# (default follows)

#chroot_list_file=/etc/vsftpd.chroot_list

#

# You may activate the "-R" option to the builtin ls. This is disabled by

# default to avoid remote users being able to cause excessive I/O on large

# sites. However, some broken FTP clients such as "ncftp" and "mirror" assume

# the presence of the "-R" option, so there is a strong case for enabling it.

#ls_recurse_enable=YES

pam_service_name=vsftpd

userlist_enable=YES

#enable for standalone mode

listen=YES

tcp_wrappers=YES

Do the following steps as:

1.vi /etc/exports

/local*.example.com(rw,sync) trusted.cracker.org(ro,sync)

service nfs start | restart

service portmap start | restart

chkconfig nfs on

chkconfig portmap on

In Linux to share the data we use the /etc/exports file. Pattern is:

Pathclient(permission)

Shared Directory Path, Client can be single host or domain name or ip address. Permission should specify without space with client lists in parentheses. NFS is RPC service so portmapper service should restart after starting the nfs service. We can specify multiple clients’ list separating by space with different shared option.

Very Easy question, nameserver is specified in question,

1.vi /etc/resolv.conf

nameserver 192.168.0.254

2.host server1.example.com

Do the following steps as:

hostname station?.example.comThis will set the host name only for current session. To set hostname permanently.

vi /etc/sysconfig/network

HOSTNAME=station?.example.com

service network restart

The LVM system organizes hard disks into Logical Volume (LV) groups. Essentially, physical hard disk partitions (or possibly RAID arrays) are set up in a bunch of equal-sized chunks known as Physical Extents (PE). As there are several other concepts associated with the LVM system, let's start with some basic definitions:

Physical Volume (PV)is the standard partition that you add to the LVM mix. Normally, a physical volume is a standard primary or logical partition. It can also be a RAID array.

Physical Extent (PE)is a chunk of disk space. Every PV is divided into a number of equal sized PEs. Every PE in a LV group is the same size. Different LV groups can have different sized PEs.

Logical Extent (LE)is also a chunk of disk space. Every LE is mapped to a specific PE.

Logical Volume (LV)is composed of a group of LEs. You can mount a filesystem such as /home and /var on an LV.

Volume Group (VG)is composed of a group of LVs. It is the organizational group for LVM. Most of the commands that you'll use apply to a specific VG.

1.Verify the size of Logical Volume:lvdisplay /dev/vg0/lv1

2.Verify the Size on mounted directory:df –h or df –h mounted directory name

3.Use :lvextend –L+400M /dev/vg0/lv1

4. ext2online –d /dev/vg0/lv1to bring extended size online.

5. Again Verify using lvdisplay and df –h command.

To automatically mount at boot time we use the /etc/fstab file. Because /etc/rc.d/rc.sysinit file reads and mount all file system specified in /etc/fstab. To mount Network Sharing Files also use the /etc/fstab but filesystem is nfs.

vi /etc/fstab

192.168.0.254:/data/commonnfsdefaults0 0

reboot the system.

Do the following steps as:

1.First check the size of Logical Volume: lvdisplay /dev/vo/myvol

2.Increase the Size of Logical Volume: lvextend -L+121M /dev/vo/myvol

3.Make Available the size on online: ext2online /dev/vo/myvol

4.Verify the Size of Logical Volume: lvdisplay /dev/vo/myvol

5.Verify that the size comes in online or not: df -h

We can extend the size of logical Volume using the lvextend command. As well as to decrease the size of Logical Volume, use the lvresize command. In LVM v2 we can extend the size of Logical Volume without unmount as well as we can bring the size of Logical Volume on online using ext2online command.

Think while Problems occurred on booting System on Runlevel 5 (X Window).

/tmp is full or not

Quota is already reached

Video card or resolution or monitor is misconfigured.

xfs service is running or not.

Do These:

1.df –h /tmp/tmp is full remove the unnecessary file

quota usernameif quota is already reached remove unnecessary file from home directory.

Boot the System in runlevel 3.you can pass the Kernel Argument from boot loader.

Use command: system-config-displayIt will display a dialog to configure the monitor, Video card, resolution etc.

Set the Default Runlevel 5 in /etc/inittab

id:5:initdefault:

6.Reboot the System you will get the GUI login Screen.

By Default system accept the logs only generated from local host. To accept the Log from other host configure:

vi /etc/sysconfig/syslog

SYSLOGD_OPTIONS="-m 0 -r"

Where

-m 0 disables 'MARK' messages.

-r enables logging from remote machines

-x disables DNS lookups on messages recieved with -r

service syslog restart

#vi /etc/resolv.conf

nameserver 172.24.254.254

# dig server1.example.com

#host server1.example.com

DNS is the Domain Name System, which maintains a database that can help your computer translate domain names such as to IP addresses such as 216.148.218.197. As no individual DNS server is large enough to keep a database for the entire Internet, they can refer requests to other DNS servers.

DNS is based on thenameddaemon, which is built on the BIND (Berkeley Internet Name Domain) package developed through the Internet Software Consortium

Users wants to access by name so DNS will interpret the name into ip address. You need to specify the Address if DNS server in each and every client machine. In Redhat Enterprise Linux, you need to specify the DNS server into /etc/resolv.conf file.

After Specifying the DNS server address, you can verify using host, dig and nslookup commands.

Do the following steps as:

1.iptables –t filter –A INPUT –s ! 192.168.0.0/24 –p tcp –d 192.168.0.254 --dport 20 –j DROP

2.iptables –t filter –A INPUT –s ! 192.168.0.0/24 –p tcp –d 192.168.0.254 --dport 21 –j DROP

iptables is the build-in firewall tools, used to filter the packets and for nat. By identifying Source Address, Destination Address, type of protocol, source and destination port we can filter the packets.

-sSource Address

-dDestination Address

-pLayer 3 Protocol

-dDestination Address

--sportSource Prot

--dportDestination Port

-iIncoming Interface

-oOutgoing Interface

-tTable either filter or nat or mangle

-AChain can be either INPUT, OUTPUT, FORWARD, PREROUTING, POSTROUTING.

Do the following steps as:

1.ftp ftp://server1.example.com

2.Login as an anonymous and download the file.

3.Copy the file in /var/www/html if you downloaded in another location.

4.service httpd restart

5.Test using links: links

Check the SELinux context of index.html file, should like this:

-rw-r--r-- root root system_u:object_r:httpd_sys_content_t /var/www/html/index.html

If SELinux Context is mismatched, use the restorecon –R /var command

Do the following steps as:

1.vi /etc/mail/local-host-names

example.com

2.vi /etc/mail/sendmail.mc

dnl # DEAMON_OPTIONS(`Port=smtp,Addr=127.0.0.1,Name=MTA`)dnl

3.m4 /etc/mail/sendmail.mc >/etc/mail/sendmail.cf

4.vi /etc/mail/access

example.comRELAY

RELAY

5.service sendmail start | restart

6.chkconfig sendmail on

/etc/mail/local-host-names file contains the aliases to hostname. Mail server program reads the /etc/mail/sendmail.cf. To change the configuration on mail server, we should edit the /etc/mail/sendmail.mc file and should generate the sendmail.cf using m4command.

By default sendmail server allows to connect to local host only. So we should edit the /etc/mail/sendmail.mc file to allow connect to other hosts.

By default sendmail server will not forward mail. we should specify on /etc/mail/access to relay or to block mail coming from domain or network or individual email address.

Here your Local LAN means your domain named example.com.

1.vi /etc/mail/local-host-names

example.com

2.vi /etc/mail/sendmail.mc

dnl # DEAMON_OPTIONS(`Port=smtp,Addr=127.0.0.1,Name=MTA`)dnl

3.m4 /etc/mail/sendmail.mc >/etc/mail/sendmail.cf

4.vi /etc/mail/access

192.168.0RELAY

5.service sendmail start | restart

6.chkconfig sendmail on

/etc/mail/local-host-names file contains the aliases to hostname. Mail server program reads the /etc/mail/sendmail.cf. To change the configuration on mail server, we should edit the /etc/mail/sendmail.mc file and should generate the sendmail.cf using m4 command.

By default sendmail server allows to connect to local host only. So we should edit the /etc/mail/sendmail.mc file to allow connect to other hosts.

By default sendmail server will not forward mail. we should specify on /etc/mail/access to relay or to block mail coming from domain or network or individual email address.

7.vi /etc/aliases

john:jane

8.newaliases

We can redirect the mail of one user to another user using /etc/aliases file. In example all mail of john goes to jane user.

Do the following steps as:

1. Rename the file named.caching-nameserver.conf into named.conf file located into /var/named/chroot/etc

#mv /var/named/chroot/etc/named.caching-nameserver.conf /var/named/chroot/etc/named.conf

2. Check the permission and ownership as well as SELinux Context should be like as:

-rw-r----- root named system_u:object_r:named_conf_t /var/named/chroot/etc/named.conf

If selinux context is mismatch use the restorecon –R /var command

3.vi /etc/named.conf

zone “example.com” IN {

type master;

file “example.com.zone”;

};

/var/named/chroot/etc/named.conf file is used to register the zone as well as specify the global option for DNS server. There are two types of zone, i. Master, which contains the original data. ii. Slave, backup of master. Here is the example of master zone configuration.

4.vi /var/named/chroot/var/named/example.com.zone

$TTL 345345

@ IN SOA @ webmaster.example.com.(

101;Serial Number

1H;Refresh Time

1M;Retry Time

1W;Expire Time

1D;Minimum Time to Live

)

@ IN NS 192.100.0.X

www 0 IN A 192.100.0.1

www 0 IN A 192.100.0.2

www 0 IN A 192.100.0.3

www 0 IN A 192.100.0.4

www 0 IN A 192.100.0.5

3.service named start

4.rndc reload

5.chkconfig named on

6. Check the permission as well as SELinux Context should like this:

-rw-r--r-- root named root:object_r:named_zone_t /var/named/chroot/var/named/example.com.zone

If selinux context is mismatch use the restorecon –R /var command

7.service named start

8.rndc reload

9.chkconfig named on

Zone file should create on /var/named/chroot/var/named. Default Directory Path is specified on /var/named/chroot/etc/named.conf file.

$TTLTime To Live, How much seconds cache server stores the information about DNS. And Five Parameters specified Serial Number used by slave to synchronize withmaster server. Refresh and Retry Time used by slave server. NS is the Name (DNS) server where lookup the domain. A (Associated IP) for particular host.

Do the following steps as:

1.vi /etc/hosts.deny

vsftpd:ALL EXCEPT .example.com

We can secure the services using tcp_wrappers. There are main two files, /etc/hosts.allow and /etc/hosts.deny.

There will be three stage access checking

-Is access explicitly permitted? Means permitted from /etc/hosts.allow?

- Otherwise, Is access explicitly denied? Means denied from /etc/hosts.deny?

- Otherwise, by default permit access if neither condition matched.

To deny the services we can configure /etc/hosts.deny file using ALL and EXCEPT operation. Pattern of /etc/hosts.allow and /etc/hosts.deny file is:

Demon_list:client_list:options

In Client list can be either domain name or IP address.

Do the following steps as:

1.vi /etc/vsftpd/vsftpd.conf

anon_upload_enable=yes

chown_uploads=yes

chown_username=username

2.service vsftpd start| restart

3.directory owner should be ftp user: chown ftp directory path allowedto upload files.

4.Write permission should be set to owner user.

By default anonymous user can only download files from the ftp. Should write anon_upload_enable=yes to enable anonymous upload files. Default Directory for anonymous is /var/ftp.

Do the following steps as:

1.vi /etc/security/time.conf

login;*;user15|user16;Sa0000-2400

2.vi /etc/pam.d/login

accountrequiredpam_time.so

For Time based authentication, we should configured in /etc/security/time.conf

Syntax of /etc/security/time.conf

services;ttys;users;times

services

is a logic list of PAM service names that the rule applies to.

ttys

is a logic list of terminal names that this rule applies to.

users

is a logic list of users to whom this rule applies.

times

the format here is a logic list of day/time-range entries the days are specified by a sequence of two character entries, MoTuSa for example is Monday Tuesday and Saturday. Note that repeated days are unset MoMo = no day, and MoWk = all weekdays bar Monday. The two character combinations accepted are

Mo Tu We Th Fr Sa Su Wk Wd Al

the last two being week-end days and all 7 days of the week respectively. As a final example, AlFr means all days except Friday.

pam_time modules checks the file /etc/security/time.conf for authentication. So, we should call the pam_time modules in /etc/pam.d/login.

Do the following steps as:

1.vi /etc/squid/squid.conf

#detault:

http_port8080

#Recommended minimum configuration:

# Near the src acl src section

acl allownet src 192.168.0.0/255.255.255.0

acl msnnet dstdomain .msn.com

#Default:

# http_access deny all

#Under Herehttp_access deny msnnet

http_access allow allownet

2.service squid start

3.chkconfig squid on

squid is a proxy caching server, using squid we can share the internet, block the internet, to certain network. First we should define the port for squid, the standard port for squid is 3128. We can run squid on different port by specifying http_port portnumber.

To block or allow the Internet access to hosts, we should create the acl (Access Control List). In this file we can specify only the IP address.

Example: acl aclname src IP/NetmaskAfter creating acl we can block or allow the Internet to specified acl.

http_access allow | deny alcname

Do the following steps as:

vi /etc/resolv.conf

nameserver 172.24.254.254

host server1.example.com

When root unable to login into the system think:

1. Is password correct?

2. Is account expired?

3. Is terminal Blocked?

Do these Steps:

Boot the System on Single user mode.

Change the password

Check the account expire date by using chage –l root command.

If account is expired, set net expire date: chage –E “NEVER” root

Check the file /etc/securettyWhich file blocked to root login from certain terminal.

If terminal is deleted or commented write new or uncomment.

Reboot the system and login as a root.

Do the following steps as:

1.First check the size of Logical Volume: lvdisplay /dev/vo/myvol

2.Make sure that the filesystem is in a consistent state before reducing:

# fsck –f /dev/vo/myvol

3.Now reduce the filesystem by 200MB.

# resize2fs /dev/vo/myvol 200M

4.It is now possible to reduce the logical volume.

#lvreduce /dev/vo/myvol –L 200M

4.Verify the Size of Logical Volume: lvdisplay /dev/vo/myvol

5.Verify that the size comes in online or not: df -h

Do the following steps as:

1. Use fdisk /dev/hdaTo create new partition.

Type nFor New partition

It will ask for Logical or Primary Partitions. Press l for logical.

It will ask for the Starting Cylinder: Use the Default by pressing Enter Key.

Type the Size: +100MYou can Specify either Last cylinder of Size here.

Press P to verify the partitions lists and remember the partitions name. Default System ID is 83 that means Linux Native.

Type t to change the System ID of partition.

Type Partition Number

Type 82 that means Linux Swap.

Press w to write on partitions table.

Either Reboot or use partprobe command.

mkswap /dev/hda?To create Swap File system on partition.

swapon /dev/hda?To enable the Swap space from partition.

free –mVerify Either Swap is enabled or not.

vi /etc/fstab

/dev/hda?swapswapdefaults0 0

Reboot the System and verify that swap is automatically enabled or not.