RH302 RHCE (Redhat Certified Engineer) Questions and Answers

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

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 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 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:

1.vi /etc/exports

/data*.example.com(rw,sync)

2.service nfs start | restart

3.service portmap start | restart

4.chkconfig nfs on

5.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.

At exam Lab example.com domain resides on 172.24.0.0/16 Network and my133t.org resides on 172.25.0.0/16 Network.

1.vi /etc/squid/squid.conf

#detault:

http_port8080

#Recommended minimum configuration:

# Near the src acl src section

acl allownet src 172.24.0.0/255.255.0.0

acl denynet src 172.25.0.0/255.255.0.0

#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.

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/squid/squid.conf

#detault:

http_port8080

#Recommended minimum configuration:

# Near the src acl src section

acl mynet src 192.168.0.0/255.255.255.0

#Default:

# http_access deny all

#Under Herehttp_access allow mynet

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:

1.visudo

# User alias Specification

User_alias LIMITEDTRUST=peter

# Cmnd alias Specification

Cmnd_alias MINIMUM=/usr/sbin/useradd, /usr/bin/passwd, /usr/sbin/groupadd, /usr/sbin/userdel, /usr/sbin/groupdel, /usr/sbin/usermod

#User Privilege Specification

LIMITEDTRUST ALL=MINIMUM

2.Login as peter user and run sudo useradd username

Using Sudo we can give root level privilege on commands. Visudo is the sudo editor. In user alias Specification we create the user alias and in Cmnd alias Specification, we create the command alias. In User Privilege Specification section, list the users, groups allowed to use the sudo.

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/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/httpd/conf.d/ssl.conf

<VirtualHost 192.100.0.2>

ServerNamewww.rhce.com

DocumentRoot /var/www/rhce

DirectoryIndex index.html index.htm

ServerAdminwebmaster@rhce.com

SSLEngine on

SSLCertificateFile/etc/httpd/conf/ssl.crt/server.crt

SSLCertificateKeyFile/etc/httpd/conf/ssl.key/server.key

</VirtualHost>

2.cd /etc/httpd/conf

3.make testcert

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

5.service httpd start|restart

6.chkconfig httpd on

Apache can provide encrypted communications using SSL (Secure Socket Layer). To make use of encrypted communication, a client must request to https protocol, which is uses port 443. For HTTPS protocol required the certificate file and key file.

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.iptables –t filter –A INPUT –s ! 192.168.0.0/24 –p tcp --dport 22 –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.

ssh service use the 22 port so we can block connection from outside the LAN.

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.

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.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.

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. resize2fs /dev/vg0/lv1to bring extended size online.

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

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

Do the following steps as:

vi /etc/resolv.conf

nameserver 172.24.254.254

host server1.example.com

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:

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

DEVICE=eth0

BOOTPROTO=static

ONBOOT=yes

IPADDR=x.x.x.x

NETMASK=x.x.x.x

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:

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.

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:

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.

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.

Do the following steps as:

1.Open the Browser either firefox or links

2.Type :http://localhost:631

3.Click on Manage Printer

4.Click on Add Printer

5.Type Queue name like stationx and click on continue

6.Type Device type or printing Protocol: i.e Internet printing Protocol

7.Click on Continue

8.Type Device URL: ipp://server1.example.com/printers/printerx

9.Click on Continue

10.Select RAW Model printer

11.Click on Continue

12.Test by sending the printing job

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 /document

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.usermod -G sysadmin john

2.usermod –G sysadmin jane

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.rpm –ivh ftp://server1.example.com/pub/zsh-*

2.Package will install

rpm command is used to install, update and remove the package, -i means install, -v means verbose and -h means display the hash mark.

Do the following steps as:

1.lvextend –L+200M /dev/test0/testvolume1

Use lvdisplay /dev/test0/testvolume1)

2.ext2online –d /dev/test0/testvolume1

lvextend command is used the increase the size of Logical Volume. Other command lvresize command also here to resize. And to bring increased size on online we use the ext2online command.

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.Open the Browser and type the above URL.

2.Fill the form as required all information.

Very Tricky question from redhat. Actually question is giving scenario to you to implement quota to neo user. You should apply the quota to neo user on /home that neo user shouldn’t occupied space more than 70K.

1.vi /etc/fstab

LABEL=/home/homeext3defaults,usrquota0 0To enable the quota on filesystem you should mount the filesystem with usrquota for user quota and grpquota for group quota.

2.touch /home/aquota.userCreating blank quota database file.

3.mount -o remount /homeRemounting the /home with updated mount options. You can verify that /home is mounted with usrquota options or not using mount command.

4.quotacheck -u /homeInitialization the quota on /home

5.edquota –u neo /homeQuota Policy editor

See the snapshot

1 Disk quotas for user neo (uid 500):

2 Filesystem blocks soft hard inodes soft hard

4 /dev/mapper/vo-myvol 2 30 70 1 0 0

Can you set the hard limit 70 and soft limit as you think like 30.

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

11. Verify by mounting on current Sessions also:

mount /dev/hda? /data

Do the following steps as:

Quotas are used to limit a user's or a group of users' ability to consume disk space. This prevents a small group of users from monopolizing disk capacity and potentially interfering with other users or the entire system. Disk quotas are commonly used by ISPs, by Web hosting companies, on FTP sites, and on corporate file servers to ensure continued availability of their systems.

Without quotas, one or more users can upload files on an FTP server to the point of filling a filesystem. Once the affected partition is full, other users are effectively denied upload access to the disk. This is also a reason to mount different filesystem directories on different partitions. For example, if you only had partitions for your root (/) directory and swap space, someone uploading to your computer could fill up all of the space in your root directory (/). Without at least a little free space in the root directory (/), your system could become unstable or even crash.

You have two ways to set quotas for users. You can limit users by inodes or by kilobyte-sized disk blocks. Every Linux file requires an inode. Therefore, you can limit users bythe number of files or by absolute space. You can set up different quotas for different filesystems. For example, you can set different quotas for users on the /home and /tmp directories if they are mounted on their own partitions.

Limits on disk blocks restrict the amount of disk space available to a user on your system. Older versions of Red Hat Linux included LinuxConf, which included a graphical tool to configure quotas. As of this writing, Red Hat no longer has a graphical quota configuration tool. Today, you can configure quotas on RHEL only through the command line interface.

1. vi /etc/fstab

/dev/hda11/dataext3defaults,usrquota 1 2

2. Either Reboot the System or remount the partition.

Mount –o remount /dev/hda11 /data

3. touch /data/aquota.user

4. quotacheck –ufm /data

5. quotaon -u /data

6. edquota –u user1 /data

and Specified the Soft limit and hard limit on opened file.

To verify either quota is working or not:

Soft limit specify the limit to generate warnings to users and hard limit can’t cross by the user. Use the quota command or repquota command to monitor the quota information.

#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.

You should know about the /etc/inittab file, where default runlevel will define. And Much more runlevel specific Scripts are called here.

Actually that problem will occur if you don’t specify the default runlevel.

Reboot the system

Boot the System on single user mode.

Except for a normal boot of Linux, single-user mode is the most commonly used option. This is the system maintenance mode for experienced Linux administrators. It allows you to perform clean backups and restores to any partitions as needed from local hardware. It also allows you to run administration commands, recover or repair password and shadow password files, run filesystem checks, and so forth.

vi /etc/inittab and Write

id:runlevel:initdefault:

Standard Runlevels in RedHat Enterprise Linux

Runlevel

Description

0

Halt

1

Single-user mode, for maintenance (backups/restores) and repairs

2

Multiuser, without networking

3

Multiuser, with networking

4

Unused

5

X11, defaults to a GUI login screen. Logins bring the user to a GUI desktop.

6

Reboot (never set initdefault in /etc/inittab to this value!)

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.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.

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

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

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.dump -0u –f /tmp/back /dev/hda4

dump is the standard backup utility. According to the questions, fullback should take. –0 means fullback, -u means update the /etc/dumpdates which maintains the backup record and -f means filename. If you are directly taking backup into other device, you can specify the device name.

e dump -0u -f /dev/st0 /dev/hda4. Where hda4 is a separate partition mounted on /home.

Do the following steps as:

1.Open the Browser and type the above URL.

2.Fill the form as required all information.

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.

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.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