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

RHCT RHCE Exam: practice prepration questions

RHCT RHCE Exam: practice prepration questions

Question:What file do you edit to set the default runlevel?

Answer: /etc/inittab

RHCT RHCE Exam: practice questions

RHCE RHCT Practice questions of the Day !

Question:How you can check status of network interface ?

Answer : # ifconfig eth0

Number of open files per process in RHEL4 redhat Linux

In RHEL4 (redhat hat enterprise Linux 4 AS ) running kernel 2.6 the number of open files per process is still limited to 1024. you can do ulimit -a to see number of open files per user :

[root@firefox] /# ulimit -a

core file size (blocks) 1000000
data seg size (kbytes) unlimited
file size (blocks) unlimited
max memory size (kbytes) unlimited
stack size (kbytes) 8192
cpu time (seconds) unlimited
max user processes unlimited (1)
pipe size (512 bytes) 8
open files 1024
virtual memory (kbytes) 2105343


To Increases the system limit on open files for instance a process on change the number of open files for Oracle , IB DB2 databases in redhat enterprise Linux (RHEL4) :

#ulimit -n 90000

To make changes permanent add soft and hard limits in /etc/security/limits.conf file :

* soft nofile 90000
* hard nofile 90000

RHCE RHCT Exam: RHCE Certification Training

Red Hat RHCE certification training is experiencing a great demand within the IT industry.
In recent years, the RHCE certification has become a global standard for many successful IT companies,increasing the importance of having a RHCE Red Hat certification.If you are interested in passing the RHCE certification exam and the RHCE certification testing requirements to start earning that high paying RHCE certification salary you always wanted. Then you have to read redhatcert.blogspot.com where i am putting tips,quetions training books,site that will ensure you pass your Red Hat RHCE exams on your first try.
As i was able to pass my RHCT exam .you can use other free RHCE materials and free RHCE study guide resources,but only Redhatcert Blog delivers you the most accurate, current and updated tips for RHCE certification.

Looking to become an RHCE Red Hat certified professional? Would you like to reduce or minimize your RHCE certification cost? Do you want to pass all of the RHCE certification tests? If you answered YES, then look no further. Keep reading this Blog and i have added seach on my Blog .I am trying to add best resource for RHCE certification training solutions that cover all core topics and RHCE certification requirements found in the RHCE certification test.

RHCT RHCE Exam: questions

For RHCT and RHCE exam questions, you should know about networking as it is required for these exams under Networking configuration :

• network card/device is recognised as eth0 in redhat linux and other flavours of linux
• ifconfig eth0 will display ip address for network interface
• you should expect questions in RHCE/RHCT exam to bring up and down network interface:
• ifup eth0
• ifdown eth0
• For RHCT/RHCE exam question you should know network configuration files:
• /etc/sysconfig/network-scripts/ifcfg-eth0 is network configuration file

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.30.29
NETMASK=255.255.255.0
GATEWAY=192.168.30.1

• For RHCT/RHCE exam you should know how to change static ip to dhcp
• Simply change BOOTPROTO to dhcp from none

• you can also run system-config-network to change these settings by GUI but for RHCT and RHCE exam you should know how to change network setting using command line that will save time as time is critical in RHCT and RHCE exams.
  

RHCT RHCE Exam :Redhat Linux Exam Certification Tip 1

RHCE RHCT Linux Certification Exam :Tip 1

Since RHCT and RHCE exam are Performance based exam, you don't need any book or Exam Cram. I realized this when i passed my RHCT exam without reading a book. All you need is PC running Linux. If you don't have PC at work or at home ..Buy one PC , belive me this will help you for RHCT and RHCE Linux certification Exam.Best tip for RHCE/RHCT exam is to have hands on experience... a pc running linux at home

If you already have PC then for installing Linux you have to partition your har drive and this is critical step , if you are not an PC expert you might loose your data while partitioning your single har drive and might loose important data. But here is good news using VMware you can install Redhat Linux on your windows operating system. Search this blog on your left you will find where and how you can get Vmware.

RHCE RHCT Exam: How to enable root telnet for redhat enterprise Linux RHEL4

How to enable root telnet for redhat enterprise Linux RHEL4:

To enable direct telnet for root account on redhat linux enterprise servers ( i have done wthis on RHEL3 and RHEL4 without any issues ) over the network :

under /etc/ directory edit /etc/securetty file and add pts entries :

pts/0
pts/1
pts/2
pts/3
pts/4
pts/5
pts/6
pts/7
pts/8
pts/9
pts/10

or Just remove /etc/securetty file alltogether , i prefer moving /etc/securetty it.

mv /etc/securetty /etc/securetty.sav

Bingo root telnet is enabled now ... on redhat enterprise Linux 4 .That's all you need to do to enable telnet access for root account on Linux servers. Root access is activated right away you don't need to restart any services on redhat linux .


Warning : telnet is not secure and you should be using SSH only for logins on RHEL4.Keep reading redhatcert blog to find out how to enable SSH logins on redhat enterprise Linux 4.

RHCE RHCT Linux EXAM CRAM

RHCE and RHCT Linux Exam Cram :

Although there are several books available online and in stores for RHCE and RHCT Exam Cram.But Buying Linux Exam Cram doen't make any sense. There are books out there :

• RHCE Linux Exam Cram: RH302.
• LPIC I Exam Cram 2 : Linux Professional Institute Certification (Exam Cram 2)

Don't Buy any more Linux "Exam Cram" because Linux is performance based exam.I don't understand there are so many Linux Exam Cram book out there and many websites claiming Exam Cram online to pass RHCT and RHCE exam. Truth is there are no multiple choice questions in RHCE and RHCT exam . so..... don't get fooled and please don't purchase any Linux exam cram for RHCT and RHCE.. If you really want to purchase any RHCE/RHCT exam book
buy RHCE exam study Guide RH302

But again no linux exam cram ....don't buy any linux exam cram and don't get fooled.