Do the following steps as:

1.vi /etc/named.conf

options {

forwarders { 192.168.22.250; };

forward only;

};

2. service named start | restart

Caching-only name server forwards a request to another name server or to the root name servers in orders to determine the authoritative name server for the resolution. Once resolution has taken place, the caching-only name server stores the resolved information in a cache for the designated time to live period.

Do the following steps as:

1.vi /etc/hosts.deny

sshd:ALL EXCEPT .example.com

or

1.vi /etc/hosts.deny

sshd:ALL

2.vi /etc/hosts.allow

sshd:.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/named.conf

zone “example.com” IN {

type master;

file “example.com.zone”;

};

/etc/named.conf file is used to register the zone as well as specify the global option for DNS. There are two types of zone, i. Master, which contains the original data. ii. Slave, backup of master. Here master zone is configured and file name is specified “example.com.zone”, which should be created in /var/named/chroot/var/named/

2.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

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

$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 with master 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. DNS has mechanism to load balance the request from clients. You can verify using hostwww.example.com command.

Do the following steps as:

1.vi /etc/httpd/conf/httpd.conf

NameVirtualHost 192.100.0.X

<VirtualHostwww.abc.com >

ServerNamewww.abc.com

DocumentRoot /var/www/abc/

DirectoryIndexindex.html

ServerAdminwebmaster@abc.com

ErrorLog logs/error_abc.logs

CustomLog logs/custom_abc.logs common

</VirtualHost>

<VirtualHostwww.example.com >

ServerNamewww.example.com

DocumentRoot /var/www/example/

DirectoryIndexindex.html

ServerAdminwebmaster@example.com

ErrorLog logs/error_example.logs

CustomLog logs/custom_example.logs common

</VirtualHost>

2.Create the directory and index page on specified path. (Index page can download fromftp://server1.example.comat exam time)

3.service httpd start| restart

4.chkconfig httpd on

5.links http://www.abc.com

6.links http://www.example.com

For Name based Virtual Hosting, we should specified the IP address on which we are going to host the multiple sites using NameVirtualHost options.

ServerName means you FQDN, already lookup on DNS

DirectoryRoot path for web documents for this site.

DirectoryIndex default page for websites.

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

192.168.0RELAY

@cracker.orgREJECT

5.service sendmail start | restart

6.chkconfig dovecot on

7.vi /etc/dovecot.conf

protocols = pop3 pop3s imap imaps

8.service dovecot start | restart

9.chkconfig dovecot on

10.vi /etc/aliases

user5:user2

11.newaliases

/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.

By default dovecot service start only the imap protocol. To start pop protocol with dovecot, we should write in /etc/dovecot.conf file.

Using /etc/aliases file we can map the user name to send mail of one user to another user. To rebuild database we use the newaliases command.

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

write list=john

browsable=yes

2.smbpasswd -a john

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.

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.

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 NFS Image 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 NFS Server Name and Redhat Enterprise Linux Directory.

Specify the NFS Server: 192.168.0.254

Directory: /var/ftp/pub

8. After Connecting to the NFS Server Installation start in GUI. Go up to 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 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.usermod -G sysusers jeff

2.usermod –G sysuser marion

3.Verify by reading /etc/group file

Using usermod command we can make user belongs to different group. There are two types of group one primary and another is secondary. Primary group can be only one butuser can belongs to more than one group as secondary.

usermod -g groupname usernameTo change the primary group of the user

usermod -G groupname usernameTo make user belongs to secondary group.

Do the following steps as:

1.useradd jane

2.useradd john

useradd command is used to create the user. All user’s information stores in /etc/passwd and user;s shadow password stores in /etc/shadow.

Do the following steps as:

1.rpm -ivh ftp://server1.example.com/pub/updates/kernel-2.6.19-11.i686.rpm

2.vi /etc/grub.conf

default=1Change this value to 1

timeout=5

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

hiddenmenu

title Red Hat Enterprise Linux ES (2.6.19-11)

root (hd0,0)

kernel /vmlinuz-2.6.19-11.EL ro root=LABEL=/ rhgb quiet

initrd /initrd-2.6.19-11.EL.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=/ rhgb quiet

initrd /initrd-2.6.9-5.EL.img

According question that kernel is available to anonymous user. You can directly install from the ftp server using rpm command.

When you install the kernel, it will write on /etc/grub.conf file. You can set the default kernel by changing the default value. See on the output of /etc/grub.conf file that new kernel is on first title so it’s index is 0 and previous kernel’s index is 1.

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:

1.echo “1” >/proc/sys/net/ipv4/ip_forward

2.vi /etc/sysctl.conf

net.ipv4.ip_forward = 1

If you want to use the Linux System as a Router to make communication between different networks, you need enable the IP forwarding. To enable on running session just set value 1 to /proc/sys/net/ipv4/ip_forward. As well as automatically turn on the IP forwarding features on next boot set on /etc/sysctl.conf file.

Do the following steps as:

1.Create a partition having size 5 GB and change the syste id ‘8e’.

2.use partprobe command

3.pvcreate /dev/hda9Suppose your partition number is hda9.

4.vgextend test0 /dev/hda9vgextend command add the physical disk on volume group.

5.lvextend –L+5120M /dev/test0/lvtestvolume

6.verify using lvdisplay /dev/test0/lvtestvolume.

Do the following steps as:

1. Create the repository file

#vi /etc/yum.repos.d/server1.repo

[station?]

name=station?

baseurl=ftp://server1.example.com/pub/

enabled=1

gpgcheck=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

# yum install

Do the following steps as:

1.chmod 770 /storage

2.Verify using : ls –ld /storage

Preview should be like:

drwxrwx--- 2 root sysusers 4096 Mar 16 18:08 /storage

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

Do the following steps as:

1. /proc is the virtual filesystem, we use /proc to modify the kernel parameters at running time.

# echo “1” >/proc/sys/net/ipv4/ip_forward

2. /etc/sysctl.confwhen System Reboot on next time, /etc/rc.d/rc.sysinit scripts reads the file /etc/sysctl.conf. To enable the IP forwarding on next reboot also you need to set the parameter.

net.ipv4.ip_forward=1

Here 0 means disable, 1 means enable.

This is boot related problem. There will be same questions repeated two times but problem is different.

First When you restart the system you will get the Error:

mount: error 15 mounting ext3

mount: error 2 mounting none

switchroot: mount failed: 22

umount /initrd/dev/: 2

Kernel Panic: no syncing: Attempted to kill init !

This error occurred in your system before showing welcome redhat linux. That means problem in grub boot loader.

Restart the System

Check the grub boot loader configuration by pressing e shortcut key.

You will see like:

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

OR

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Then Edit Boot loader to make like

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Check all lines and edit as same as above. Press b to boot the system

After booting the system you should correct the /etc/grub.conf file.

This is boot related problem. There will be same questions repeated two times but problem is different.

First When you restart the system you will get the Error:

File Not Found

mount: error 15 mounting ext3

mount: error 2 mounting none

switchroot: mount failed: 22

umount /initrd/dev/: 2

Kernel Panic: no syncing: Attempted to kill init !

This error occurred in your system before showing welcome redhat linux. That means problem in grub boot loader.

Restart the System

Check the grub boot loader configuration by pressing e shortcut key.

You will see like:

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

OR

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Then Edit Boot loader to make like

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Check all lines and edit as same as above. Press b to boot the system

After booting the system you should correct the /etc/grub.conf file.

If still you are getting Error likeFile not found, it seems that either kernel file or initrd file is missing. To troubleshoot with these problem, boot the system on rescue mode.

linux rescue

chroot /mnt/sysimage

Check the files on /boot, if not available install the kernel package from ftp or nfs server

Create the initrd image file on boot using: mkinitrd initrd-2.6.9-5.EL.img `uname –r`

It is due to either default runlevel or runlevel specific scripts.

id:?:initdefault:Where default runlevel is specified. It shouldn’t be 6.

l3:3:wait:/etc/rc.d/rc 6It reads the scripts of runlevel 6 while booting system on rulevel 3.

It should be like:

si::sysinit:/etc/rc.d/rc.sysinit

l0:0:wait:/etc/rc.d/rc 0

l1:1:wait:/etc/rc.d/rc 1

l2:2:wait:/etc/rc.d/rc 2

l3:3:wait:/etc/rc.d/rc 3 Should be like this

l4:4:wait:/etc/rc.d/rc 4

l5:5:wait:/etc/rc.d/rc 5

l6:6:wait:/etc/rc.d/rc 6

Do the following steps as:

Use netconfig command

Enter the IP Address as given station number by your examiner: example: 172.24.0.1

Enter Subnet Mask

Enter Default Gateway and primary name server

press on ok

ifdown eth0

ifup eth0

verify using ifconfig

In the lab server is playing the role of router, IP forwarding is enabled. Just set the Correct IP and gateway, you can ping to 172.25.254.254.

Do the following steps as:

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

Type nFor New partitions

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.

Press w to write on partitions table.

Either Reboot or use partprobe command.

Use mkfs –t ext3 /dev/hda?

Or

mke2fs –j /dev/hda? To create ext3 filesystem.

vi /etc/fstab

Write:

/dev/hda?/dataext3defaults0 0

Verify by mounting on current Sessions also:

mount /dev/hda? /data

Do the following steps as:

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

Type nFor New partitions

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.

Press w to write on partitions table.

Either Reboot or use partprobe command.

Use mkfs –t ext3 /dev/hda? Where ? is your partition number

Or

mke2fs –j /dev/hda? To create ext3 filesystem.

mkdir /mnt/neo

vi /etc/fstab

Write:

/dev/hda?/mnt/neoext3defaults1 2

Verify by mounting on current Sessions also:

mount /dev/hda? /mnt/neo

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 using free command that swap is automatically enabled or not.

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.

Note: Examiner will provide you the Installation startup CD. And 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 NFS Image 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 NFS Server Name and Redhat Enterprise Linux Directory.

Specify the NFS Server: 192.168.0.254

Directory: /var/ftp/pub

8. After Connecting to the NFS Server Installation start in GUI. Go up to 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 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:

1. use the authconfig or system-config-authentication

2. Select the [*] USE NIS

3. Type the NIS Domain: RHCE

4. Type Server 192.168.0.254 then click on next and ok

5. You will get a ok message.

6. Create a Directory /rhome/stationx where x is your station number.

6. vi /etc/auto.master and write at the end of file

/rhome/stationx /etc/auto.home --timeout=60

7. vi /etc/auto.home and write

*-rw,soft,intr192.168.0.254:/rhome/stationx/&

Note: please specify your station number in the place of x.

8. Service autofs restart

9. Login as the nisuser2001 or nisuser2002 on another terminal will be

Success.

According to question, RHCE domain is already configured. We have to make a client of RHCE domain and automatically mount the home directory on your system. To make a member of domain, we use the authconfig or system-config-authentication command. There a are lots of authentication server i.e NIS, LDAB, SMB etc. NIS is a RPC related Services, no need to configure the DNS, we should specify the NIS server address.

Here Automount feature is available. When user tried to login, home directory will automatically mount. The automount service reads the configuration from /etc/auto.master file. On /etc/auto.master file we specified the mount point the configuration file for mount point.

Do the following steps as:

1.groupadd sysuser

groupadd command is used to create the group and all group information is stored in /etc/group file.

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.useradd jane

2.useradd john

useradd command is used to create the user. All user’s information stores in /etc/passwd and user;s shadow password stores in /etc/shadow.

By default user1 can remove user2’s files due to directory permission to group member. We can prevent of deleting files from others users using Sticky Bits.

chmod o+t /data

Verify /data: ls -ld /data

You will get: drwxrwx—T

Do the following steps as:

1.cat >schedule

*/2 * * * * /bin/echo “Hello World” >/dev/tty8

crontab schedule

Verify using: crontab –l

service crond restart

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.

To add the scheduled file on cron job: crontab filename

To List the Cron Shedule: crontab –l

To Edit the Schedule: crontab –e

To Remove the Schedule: crontab –r

Do the following steps as:

1.rpm -ivh ftp://server1.example.com/pub/updates/kernel-2.6.9-11.i686.rpm

2.vi /etc/grub.conf

default=1Change this value to 1

timeout=5

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

hiddenmenu

title Red Hat Enterprise Linux ES (2.6.9-11)

root (hd0,0)

kernel /vmlinuz-2.6.9-11.EL ro root=LABEL=/ rhgb quiet

initrd /initrd-2.6.9-11.EL.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=/ rhgb quiet

initrd /initrd-2.6.9-5.EL.img

According question that kernel is available to anonymous user. You can directly install from the ftp server using rpm command.

When you install the kernel, it will write on /etc/grub.conf file. You can set the default kernel by changing the default value. See on the output of /etc/grub.conf file that new kernel is on first title so it’s index is 0 and previous kernel’s index is 1.

Do the following steps as:

1.vi /etc/sysconfing/network

NETWORKING=yes

HOSTNAME=station?.example.com

GATEWAY=192.168.0.254

2.service network restart

Or

1.vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

ONBOOT=yes

BOOTPROTO=static

IPADDR=X.X.X.X

NETMASK=X.X.X.X

GATEWAY=192.168.0.254

2.ifdown eth0

3.ifup eth0

This is boot related problem. There will be same questions repeated two times but problem is different.

First When you restart the system you will get the Error:

mount: error 15 mounting ext3

mount: error 2 mounting none

switchroot: mount failed: 22

umount /initrd/dev/: 2

Kernel Panic: no syncing: Attempted to kill init !

This error occurred in your system before showing welcome redhat linux. That means problem in grub boot loader.

Restart the System

Check the grub boot loader configuration by pressing e shortcut key.

You will see like:

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

OR

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Then Edit Boot loader to make like

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Check all lines and edit as same as above. Press b to boot the system

After booting the system you should correct the /etc/grub.conf file.

Maintenance mode also known as emergency mode. System boots on emergency mode when file system error occurred. It is due to unknown partition, bad filesystem specified in /etc/fstab. To slove follow the steps

Give the Root password

fdisk –lVerify the Number of parations.

Identify the Root partition, e2label /dev/hda1, e2label /dev/hda2…..

Remount the root partation on rw mode: mount –o remount,defaults /dev/hda6 /

vi /etc/fstab

Correct all partitions, mount point, mount options, file system etc.

6.Press ctrl+d

This is boot related problem. There will be same questions repeated two times but problem is different.

First When you restart the system you will get the Error:

File Not Found

mount: error 15 mounting ext3

mount: error 2 mounting none

switchroot: mount failed: 22

umount /initrd/dev/: 2

Kernel Panic: no syncing: Attempted to kill init !

Restart the System

Check the grub boot loader configuration by pressing e shortcut key.

You will see like:

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

OR

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Then Edit Boot loader to make like

root (hd0,0)

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

initrd /initrd-2.6.9-5.EL.img

Check all lines and edit as same as above. Press b to boot the system

After booting the system you should correct the /etc/grub.conf file.

If still you are getting Error likeFile not found, it seems that either kernel file or initrd file is missing. To troubleshoot with these problem, boot the system on rescue mode.

linux rescue

chroot /mnt/sysimage

Check the files on /boot, if not available install the kernel package from ftp or nfs server

Create the initrd image file on boot using: mkinitrd initrd-2.6.9-5.EL.img `uname –r`

Do the following steps as:

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.

Do the following steps as:

1.vi /etc/sysconfig/network

GATEWAY=192.168.0.254

OR

vi /etc/sysconf/network-scripts/ifcfg-eth0

DEVICE=eth0

BOOTPROTO=static

ONBOOT=yes

IPADDR=192.168.0.?

NETMASK=255.255.255.0

GATEWAY=192.168.0.254

2.service network restart

Do the following steps as:

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

Type nFor New partitions

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.

Press w to write on partitions table.

Either Reboot or use partprobe command.

Use mkfs –t ext3 /dev/hda?

Or

mke2fs –j /dev/hda? To create ext3 filesystem.

vi /etc/fstab

Write:

/dev/hda?/dataext3defaults1 2

11. Verify by mounting on current Sessions also:

mount /dev/hda? /data

Very Easy question, nameserver is specified in question,

1.vi /etc/resolv.conf

nameserver 192.168.0.254

2.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.

By default all mails to user will send to user’s spool directory. Nothing to do.

Do the following steps as:

1.vi /etc/hosts.deny

dovecot:ALL EXCEPT .example.com EXCEPT station20.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/httpd/conf/httpd.conf

NameVirtualHost 192.100.0.X

ServerNamewww.abc.com

DocumentRoot /var/www/abc/

DirectoryIndexindex.html

ServerAdminwebmaster@abc.com

ErrorLog logs/error_abc.logs

CustomLog logs/custom_abc.logs common

ServerNamewww.example.com

DocumentRoot /var/www/example/

DirectoryIndexindex.html

ServerAdminwebmaster@example.com

ErrorLog logs/error_example.logs

CustomLog logs/custom_example.logs common

2.Create the directory and index page on specified path. (Index page can download fromftp://server1.example.comat exam time)

Check the SELinux context of index page , 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

3.service httpd start| restart

4.chkconfig httpd on

5.links http://www.abc.com

6.links http://www.example.com

For Name based Virtual Hosting, we should specified the IP address on which we are going to host the multiple sites using NameVirtualHost options.

ServerName means you FQDN, already lookup on DNS

DirectoryRoot path for web documents for this site.

DirectoryIndex default page for websites.

Do the following steps as:

1.vi /etc/exports

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

Check the SELinux Context, should be like this:

-rw-r--r-- root root system_u:object_r:exports_t /etc/exports

Use the restorecon –R /etc command to restore the selinux context of the file.

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.