RedHat RH302 RHCE (Redhat Certified Engineer) Exam Practice Test

Do the following steps as:

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: 172.24.254.254

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.Create the two RAID partitions having equal size of remaining all free space.

11.Click on RAID button

12.Type mount point /archive

13.Select RAID Level 0

14.Click on ok

15. 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. Go to on that directory where you want to restore.

2. restore –rf /dev/st0

To restore from backup we use the restore command. Here backup will restore from /dev/st0 on current Directory.

Steps of Creating LVM:

Physical Disk1

Physical Disk2

Physical Disk3

Physical Volume

Volume Group

Logical Volume 1

Logical Volume 2

Logical Volume 3

1.pvcreate /dev/hda8 /dev/hda9 /dev/hda10

pvdisplay command is used to display the information of physical volume.

2.vgceate test0 /dev/hda8 /dev/hda9 /dev/hda10

vgdisplay command is used to display the information of Volume Group.

3.lvcreate –L 250M –n testvolume1 test0

lvdisplay command is used to display the information of Logical Volume.

4.lvcreate –L 250M –n testvolume2 test0

5.mkfs –t ext3 /dev/test0/testvolume1

6.mkfs –t ext3 /dev/test0/testvolume2

7.mkdir /lvtest1

8.mkdir /lvtest2

9.mount /dev/test0/testvolume1 /lvtest1

10.mount /dev/test0/testvolume2 /lvtest2

11.vi /etc/fstab

/dev/test0/testvolume2/lvtest2ext3defaults0 0

/dev/test0/testvolume1/lvtest1ext3defaults0 0

To create the LVM( Logical Volume Manager) we required the disks having ‘8e’ Linux LVM type. First we should create the physical Volume, then we can create the Volume group from disks belongs to physical Volume. lvcreate command is used to create the logical volume on volume group. We can specify the size of logical volume with –L option and name with -n option.

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:

1.usermod -G sysuser jackie

2.usermod –G sysuser curtin

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 but user 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. use the authconfig --nisserver= --nisdomain= --update

Example: # authconfig --nisserver=192.168.0.254 --nisdomain=RHCE --update

or system-config-authentication

2. Click on Enable 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 with option or system-config-authentication command. There a are lots of authentication server i.e NIS, LDAB, SMB etc. NIS is aRPC 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 used the /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.chmod g+s /archive

2.Verify using: ls -ld /archive

Permission should be like:

drwxrws--- 2 root sysuser 4096 Mar 16 18:08 /archive

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

According to question, log server is already configured. We have to configure the mail, web and dns server for log redirection.

In mail, web and dns server:

1.vi /etc/syslog.conf

mail.*@logserveraddress

2.service syslog restart

mail is the facility and * means the priority. It sends logs of mail services into log server.

While you load the X Window System, you will get the problem. Problem may caused by different error.

1.Check the /tmp is full ?

2.Check your quota, hard limit is already crossed ?

3.Check xfs service is running ?

4.Configure the Video card, Resolution, monitor type using: system-config-display (Most Probably in Redhat exam)

5.Edit the /etc/inittab to set default runlevel 5.

id:5:initdefault:

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.

Do the following steps as:

Boot the system in Single user mode

Use the passwd command

We can control the services for current session and for next reboot time. For current Session, we use service servicename start or restart or stop or status. For automatically at next reboot time:

chkconfig servicename on or off

eg: chkconfig nfs on

chkconfig portmap on

or

ntsysv

Select the nfs and portmap services.

Reboot the system and identify whether services are running or not.

#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 www.redhat.com 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.

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`

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.

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

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

Do the following steps as:

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: 172.24.254.254

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.Create the two RAID partitions having equal size of remaining all free space.

11.Click on RAID button

12.Type mount point /archive

13.Select RAID Level 0

14.Click on ok

15. 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:

useradd username

passwd username

usermod -e “date”

example: usermod -e “12 Feb 2006” user4

Verify: chage –l user4

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.

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.

We can change the permission of file/directory either character symbol method or numeric method.

Permission:

r-Read

w-Write

x-Execute

Permission Category

u- Owner User

g- Owner Group

o- Others

Operators

+Add the Permissions

-Remove the Permissions

=Assigns the Permissions

Numeric Method:

4Read

2Write

1Execute

Total: 7, total for owner user, owner group member and for others : 777

chmod u+rwx /data

chmod g+rwx /data

chmod o-rwx /data

or

chmod 770 /data

Verify the /data : ls –ld /data

You will get drwxrwx---

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:

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.

When user creates the file/directory, user owner will be user itself and group owner will be the primary group of the user.

There is one Special Permission SGID bit, when you set the SGID bit on directory,When users creates the file/directory automatically owner group will be same as a parent directory.

chmod g+s /data

Verify using: ls -ld /data

You will get: drwxrws---

Do the following steps as:

useradd user1

useradd user2

useradd user3

passwd user1

passwd user2

passwd user3

We create the user using useradd command and we change the password of user using passwd command. If you want to set the blank password use: passwd -d username.

IMAP is a very usefully protocol, but it lacks encryption. The dovecot package distributed with RHEL includes the ability to use IMAP over SSL, This requires the creation of a PEM format certificate.

cd /etc/pki/tls/ and remove the cert.pem.

Go the /etc/pki/tls/certs then use:

make dovecot.pem : Which generates the dovecot.pem certificate by reading MakeFile

Enable the imaps with Certificate and Key file protocol from /etc/dovecot.conf

vi /etc/dovecot.conf

protocols = imap imaps

ssl_cert_file = /etc/pki/dovecot/certs/dovecot.pem

ssl_key_file = /etc/pki/dovecot/private/dovecot.pem

service dovecot restart : Restart the Dovecot service

Do the following steps as:

1.vi /var/named/chroot/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/samba/smb.conf

[global]

netbios name=station?

workgroup=linuxgroup

security=share

printcap name=/etc/printcap

load printers=yes

printing=cups

[printers]

path=/var/spool/samba

browsable=yes

printable=yes

guest ok=no

writable=no

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 to share the user’s home directory.

/etc/printcap file contains all installed printers name. Printing is print system used on server.

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/hosts.deny

sshd: 192.168.0. EXCEPT 192.168.0.4

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/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/hosts.deny

ALL:.cracker.org EXCEPT trusted.cracker.org

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/security/limits.conf

user1,user2-maxlogins1

@training-maxlogins5

2.vi /etc/pam.d/system-auth

sessionrequired/lib/security/pam_limits.so

To limit the number of process or number of logins, we should configure on /etc/security/limits.conf. First Columns contains the username separated by comma or @group name. Second column either hard or soft limits. Third columns called the item, maxloigns or nproc etc.

To identify the session of users we should call the pam_limits module in /etc/pam.d/system-auth.

At exam Lab example.com domain resides on 192.168.0.0/24 Network and cracker.org resides on 192.168.1.0/24 Network.

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 denynet src 192.168.1.0/255.255.255.0

#Default:

# http_access deny all

#Under Herehttp_access allow allownet

http_access deny denynet

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 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.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

When you Boot the System, it starts on default Runlevel specified in /etc/inittab:

Id:?:initdefault:

When System Successfully boot, it will ask for username and password. But you don’t know the root’s password. To change the root password you need to boot the system into single user mode. You can pass the kernel arguments from the boot loader.

Restart the System.

You will get the boot loader GRUB screen.

Press a and type 1 or s for single mode

ro root=LABEL=/ rhgb queit s

System will boot on Single User mode.

Use passwd command to change.

Press ctrl+d

To understand the role of a boot loader, take a step back from Linux. When you boot your computer, the BIOS starts by detecting basic hardware, including your hard drives. Once it's done, it looks for the boot loader on the Master Boot Record of the first available disk. If you're working with an older PC, the BIOS can't find your boot loader unless it's located within the first 1,024 cylinders of the hard disk.

Newer BIOSes overcome this problem with Logical Block Addressing, which is also known as LBA mode. LBA mode reads 'logical' values for the cylinder, head, and sector, which allows the BIOS to 'see' a larger disk drive.

If you have multiple hard drives, there is one more caveat. If your drives are IDE hard drives, the /boot directory must be on a hard drive attached to the primary IDE controller. If your drives are all SCSI hard drives, the /boot directory must be located on a hard drive with SCSI ID 0 or ID 1. If you have a mix of hard drives, the /boot directory must be located on either the first IDE drive or a SCSI drive with ID 0. In other words, this is not an issue on the Red Hat exams unless the computer that you're tested on has more than two hard drives. And I believe that's less likely, as that would increase the cost of the exam.

If you are getting the Kernel panic error, it means it is boot loader related problem. Redhat Enterprise Linux uses the GRUB boot loader. You can pass the kernel parameter from the boot loader as well as you can correct the kernel parameter passing from boot loader from GRUB screen at boot time.

GRUB boot loader configuration file is: /etc/grub.conf

And Correct Configuration is:

default=0

timeout=5

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

hiddenmenu

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

Probably miss-configured the boot loader, so giving this problem. You can pass the correct parameter from GRUB prompt:

Table 3-3:GRUB Editing Commands

Command

Description

b

Boot the currently listed operating system

d

Delete the current line

e

Edit the current line

o

Create an empty line underneath the current line

O

Create an empty line above the current line

If you know all parameters and sequence of the boot loader you can enter in command prompt also.

Press c on GRUB screen.

Grub>root (hd0,0)

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

grub>initrd /initrd-2.6.9-5.EL.img

grub>boot

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.Verify the File whether Shared or not ? : cat /etc/exports

2.Start the nfs service: service nfs start

3.Start the portmap service: service portmap start

4.Make automatically start the nfs service on next reboot: chkconfig nfs on

5.Make automatically start the portmap service on next reboot: chkconfig portmap on

6.Verify either sharing or not: showmount –e localhost

7.Check that default firewall is running on system ? if running flush the iptables using iptables –F and stop the iptables service.

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:

Boot the system in Single user mode

Use the passwd 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 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.

Do the following steps as:

ftpftp.server1.example.com

Download thewww.html

move the downloaded file into /var/www/html

Rename the file into index.html

Check using linkshttp://stationx.example.com

/var/www/html is the default directory for httpd service. Index.html is the default directory index. To set the default page without configuring virtualhost copy the file as a index.html in /var/www/html.

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.

Note: In Exam Lab there will be two different domain example.com which is known as local domain and another is cracker.org which is called non trusted domain. So only from .example.com means allow only to example.com deny to every one.

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.