RHCE fast Track Course with RHEL5 and RHCE Exam:

Redhat has updated RHCE exam and replaced study and course material from RHEL4 with RHEL5. Redhat RH300 rapid course covers study material for RHCT and RHCE exam plus hands on exam on the 5^th day.RH300 course is designed for experience UNIX and Linux administrators who needs training and want to appear for exam using RHEL5. If you are experienced Linux administrator you can take pre-asessment questionnaires provided by redhat to determine if you are ready to take RHCE exam. Now vmware offers free virtualization to run on windows called vmware server which allows you to run Linux as virtual os on your windows XP to help you preparing for RHCE/RHCT exam. There are some issues with running vmware on windows vista Check this out before installing vmware server on your pc running windows vista.

Once you have vmware server (available free from vmware) installed you can install Fedora or RHEL5 (redhat enterprise 5 ) :

RH033 exam pre-assessment for RHCT

RH133 exam pre-assessment for RHCT

RH253 exam pre-assessment for RHCE

If you pass all these pre-assessment then you can directly go for RHCE exam, if you are doing good only for RH033 and RH133 then you should go for RHCT or need more preparation. For tips and tricks and some easy scoring keeping visiting redhat certification help site.

How to access virtual console in RHEL4/RHEL5?

RHCE RHCT Exam questions – How to access virtual console in RHEL4/RHEL 5 ?

Five virtual are provided during installation process in Redhat enterprise Linux servers. Virtual console can't be accessed using ALT-function ket

Combinations:

ALT-F1 : to access installer in text mode (RHEL4/RHEL5)

ALT-F2: to access bash shell (RHEL4/RHEL5)

ALT-F3 to view log of installer messages (RHEL4/RHEL5)

ALT-F4: to view log of kernel messages (RHEL4/RHEL5)

ALT-F5 stdout of mke2fs and grub command (RHEL4/RHEL5)

ALT-F7 : access installer in Graphical mode. (RHEL4/RHEL5)

RHCE RHCT Exam questions:Howto configure the network card in redhat enterprise Linux

RHCE RHCT Exam questions:Howto configure the network card in redhat enterprise 5 Linux :

Question. I’ve installed Red Hat enterprise Linux 5 and now added one more LAN card (NIC). How do I configure the network card from the command line? I can see 2nd my network card detected while booting the IBM server.
Answer . Red hat Linux provides following tools to make changes to Network configuration such as add new card, assign IP address, change DNS server etc.

(a) GUI tool (X Windows required) - system-config-network
(b) Command line text based GUI tool (No X Windows required) - system-config-network
(c)Edit configuration files stored in /etc/sysconfig/network-scripts/ directory

GUI can be launched using system-config-network

RHCE RHCT Exam questions : How to load USB driver in Linux

Question: RHCE RHCT Exam questions : How to load USB driver in Linux ?
Answer : in Redhat Enterprise Linux servers (RHEL3/RHEL4/RHEL5) usb drivers can be loaded on fly using modprobe command :

$modprobe usb-uhci

$modprobe usb-ohci

similarly modules can be removed or unloaded using "modprobe -r"

also insmod can be used to add module

RHCE RHCT Exam questions :

RHCE RHCT Exam questions

Question: How would you list loaded modules in Redhat Enterprise 3/4 Linux ?
Answer : lsmod

RHCE RHCT Linux Certification Exam: How to check memory usage

while Preparing for RHCE and RHCT exam certification one should know how to check memory utilization in redhat enterprise Linux. one useful command is free , you can get memory usage in megabytes and gigabytes :

[root@ldev ~]# free -m
total used free shared buffers cached
Mem: 992 975 16 0 137 628
-/+ buffers/cache: 210 781
Swap: 2047 0 2047

RHCE RHCT Linux Exam Enable vsftpd on RHEL4

Enable VSFTP on Redhat Enterprise Linux 4 update 3

To lock users in home dir:

Touch vsftpd.chroot_list ; to create file of users that are allowed to ftp outside their home dirs add root to this file

Cd /etc/vsftpd

vi vsftpd.conf

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

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

# users to NOT chroot().

chroot_list_enable=YES

chroot_local_user=YES

# (default follows)

chroot_list_file=/etc/vsftpd.chroot_list ; add root to this file

service vsftpd restart

To lock users in home dir:

Touch vsftpd.chroot_list ; to create file of users that are allowed to ftp outside their home dirs add root to this file

RHCT RHCE Exam :RHEL4 NFS issues

RHCT RHCE Exam :RHEL4 NFS issues :

Many times you have NFS exported directories mounted on Linux server get hanged. Possible sided affects just find out on my test Redhat Linux server running RHEL4 AS update 3 df start hanging. Pretty annonying . Trouble part is how to get rid off hanging df issues and find outr why it's happening.

NFS mounts are hanging simply because Server exporting NFS mount is offline or not on network. Again let's say you have 50 0r more mount point mounted on your NFS Linux client machine. You have to compare nfs mount showing in df comand output and nfs mount listed in /etc/fstab. once you find out what NFS mount is hanging you can simply go in /etc/rmtab file and remove that mount point.... and guess what you just resolved hanging nfs mount issue .

RHCE RHCT Exam Question: How to stop/start network interface

RHCE RHCT Exam Question: How to stop/start network ethernet interface:

[root@ice ~]# ifdown eth0

[root@ice ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:2A:47:7F
inet addr:192.168.0.103 Bcast:192.168.0.255 Mask:255.255.255.0
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:1899 errors:0 dropped:0 overruns:0 frame:0
TX packets:833 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:923925 (902.2 KiB) TX bytes:283867 (277.2 KiB)
Interrupt:10 Base address:0x1400

[root@ice ~]# ifup eth0

Determining IP information for eth0... done.
[root@ice ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:2A:47:7F
inet addr:192.168.0.103 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe2a:477f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1900 errors:0 dropped:0 overruns:0 frame:0
TX packets:838 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:924267 (902.6 KiB) TX bytes:284517 (277.8 KiB)
Interrupt:10 Base address:0x1400

RHCE RHCT Exam:Create and Mount filesystem in redhat enterprise Linux

RHCE RHCT Exam:Create and Mount filesystem in redhat enterprise Linux:

• Redhat Enterprise 4 Linux you can use fdisk -l to list existing partitions on your system as a part of your Lab in RH133 Course :

[root@ice ~]# fdisk -l /dev/sda

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 1318 10482412+ 8e Linux LVM
/dev/sda3 1319 1579 2096482+ 82 Linux swap
/dev/sda4 1580 2610 8281507+ 5 Extended

• Here we have unallocated extended partition . Remember you can have only 3 Primary partitions for a single disk in Redhat in our case we have SCSI disk /dev/sda where we have 3 primary partitions,with remaining unlloacted space you need to create Extended partition if you need to create more than 3 partitions .

#fdisk /dev/sda

• ON COMMAND TYPE n to create new partition , hit enter for start cylinder number and then on last cyliner i used +1024M you can use +1G as well , because i am going to create 1 GB filesystem :

Command (m for help): n
First cylinder (1580-2610, default 1580):
Using default value 1580
Last cylinder or +size or +sizeM or +sizeK (1580-2610, default 2610): +1024M
Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

Here is a catch that would be really stupid idea to reboot your Redhat enterprise Linux server to activate your partition table changes. I am sure Redhat will remove this warning in their upcoming redhat enterprise level 5 Linux version.Also you can save time in your RHCT/RHCE Certification Exam using partprobe. Note this how i am activating new partition table changes using PARTPROBE magic command.

[root@ice ~]# partprobe

[root@ice ~]# fdisk -l /dev/sda

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 1318 10482412+ 8e Linux LVM
/dev/sda3 1319 1579 2096482+ 82 Linux swap
/dev/sda4 1580 2610 8281507+ 5 Extended
/dev/sda5 1580 1704 1004031 83 Linux

• Now I have to create a directory where i need to mount new +1 GB fileystem i am going to make ext3 filesystem .

#mkdir /home

[root@ice ~]# mkfs -t ext3 /dev/sda5
[root@ice ~]# mount /dev/sda5 /home
[root@ice ~]# df -h /home
Filesystem Size Used Avail Use% Mounted on
/dev/sda5 966M 18M 899M 2% /home

Here is your +1GB home filesystem (type is ext3) ready to use . you can add this in yout /etc/fstab file to make change permanent where it will mount /home automatically and persistent to server reboots.

RHCE RHCT Exam: How to mount USB drive on RHEL4

RHCE RHCT Exam: How to mount USB drive on Redhat enterprise Linux server (RHEL4) :

Make Sure USB drive is connnected right to your Linux machine/server , i have plugged in USB thumb drive. Before connecting USB drive do a tail -f /var/log/messages , Redhat Linux sees USB drive as a SCSI device so device will be named as "sdxxx" :
[root@ice ~]# tail -f /var/log/messages
Apr 27 21:52:30 ice kernel: Attached scsi removable disk sdb at scsi1, channel 0, id 0, lun 0
Apr 27 21:52:30 ice kernel: usbcore: registered new driver usb-storage
Apr 27 21:52:30 ice kernel: sdb: assuming drive cache: write through
Apr 27 21:52:30 ice kernel: sdb: sdb1

#df -h
/dev/sdb1 124M 101M 24M 82% /media/usbdisk

USB is mounted as /dev/sdb1

RHCE and RHCT exam:exporting NFS filesystems in RHEL4

Exporting NFS filesystem in RHEL4 (Redhat enterprise Linux) servers:

To export directory /home/export you need to add an entry in /etc/exports :

/home/export parmount.ice.com(rw,sync)

make sure there is space between mount options and hostname otherwise you will get permission error on redhat linux client.

RHCE and RHCT exam: max telnet session limit reached in RHEL4

maximum telnet session limit reached in( RHEL4)Redhat Enterprise Linux :

Quick Fix if you are getting maximum telnet service_limit reached messages in /var/log/secure logs in redhat enterprise Linux servers . Awesome you don't need to reboot your RHEL4 server unlike HP-UX serves :

Getting error : xinetd [4092] :FAIL: telnet service_limit

Just change session limit from 60 for instances to some large number

#
# Simple configuration file for xinetd
#
# Some defaults, and include /etc/xinetd.d/
defaults
{
instances = 400
log_type = SYSLOG authpriv
log_on_success = HOST PID
log_on_failure = HOST
cps = 25 30
}

service telnet2
{
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
disable = no
}

#[root@ice]# service xinetd reload

RHCE RHCT Exam questions : How to check kernel in RHEL4

RHCE RHCT Exam questions : How to check kernel in RHEL4 ?

[root@ice ~]# file /sbin/init
/sbin/init: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.5, dynamically linked (uses shared libs), stripped

RHCE and RHCT exam: Memory available on RHEL4

How can you Check availale Memory on RHEL4 (Redhat Enterprise Linux servers) :

[root@ice /]# grep Mem /proc/meminfo
MemTotal: 255972 kB
MemFree: 5896 kB

RHCE RHCT EXAM :create disk paritions without reboot in RHEL4

Create partition on RHEL :Redhat Enterprise Linux without reboot :

[root@ice ~]# fdisk /dev/sda

The number of cylinders for this disk is set to 2610.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 1318 10482412+ 8e Linux LVM
/dev/sda3 1319 1579 2096482+ 82 Linux swap

Command (m for help): n
Command action
e extended
p primary partition (1-4)
e
Selected partition 4
First cylinder (1580-2610, default 1580):
Using default value 1580
Last cylinder or +size or +sizeM or +sizeK (1580-2610, default 2610):
Using default value 2610

Command (m for help): p

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 1318 10482412+ 8e Linux LVM
/dev/sda3 1319 1579 2096482+ 82 Linux swap
/dev/sda4 1580 2610 8281507+ 5 Extended
Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

Finally type partprobe to make parition change available to Redhat enterprise Linux (RHEL4) without reboot :

[root@ice ~]# partprobe /dev/sda

RHCE and RHCT exam questions

For RHCT and RHCE exam questions, you should know How to check installed packages :

For example to check whether you have firefox installed you can use rpm utility available on RedHat enterprise Linux :
[root@ice ~]# rpm -qa |grep firefox
firefox-1.0.7-1.4.3

RHCT RHCE Exam:DNS name resolution in RHEL4

DNS name resolution in RHEL4 :

/etc/resolv.conf file is used for Domain name resolution (DNS name resolution) :
search rhceexam.linux.com
nameserver 192.168.100.1
nameserver 192.168.100.2

RHCT RHCE Exam:Mounting USB drive on RHEL 4

Mounting USB drive/USB floppy drive on RHEL4

USB drive /device on Redhat Enterprise Linux is recognized as scsi device /dev/sdx (where is x is
number of next available scsi disk... example if you have two scsi disk namely sda and sdb then usb floppy drive will be sdc1

#mount /dev/sdc1 /floppy

RHCT RHCE Exam: practice prepration questions

RHCT RHCE Exam: practice prepration questions :

Question: Where do you look for changing boot loader sequence ?

Answer: on RHEL4 ( redhat enterprise Linux 4 ) /boot/grub/grub.conf