Wise people learn when they can; fools learn when they must - Arthur Wellesley

Thursday 23 February 2017

RHEL6- (11)- ROUTES & DEFAULT GATEWAY –P3


RHEL6-(11)-ROUTES & DEFAULT GATEWAY                              -P3
Under Routes & Default Gateway:
ROUTES & DEFAULT GATEWAY –P1
ROUTES & DEFAULT GATEWAY –P2
ROUTES & DEFAULT GATEWAY –P3

Well, we covered a lot.
Next is to have two default routes on system.

Till we have one default gateway configured in our system and all traffic was routed with that.

Now the requirement is as follows,

192.168.234.0 – eth1 & eth2 – via 192.168.234.2
192.168.110.0 – eth0 & eth3 – via 192.168.110.1
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RHEL6-(10) -ROUTES & DEFAULT GATEWAY –P2


RHEL6-(10)-ROUTES & DEFAULT GATEWAY                             -P2

Under Routes & Default Gateway:

ROUTES & DEFAULT GATEWAY –P1
ROUTES & DEFAULT GATEWAY –P2
ROUTES & DEFAULT GATEWAY –P3

In UNIX systems routing table consists the information about packet forwarding.


Route add
Route delete
Making route persistent
Default route configuration

[root@rhel6-server ~]# ip route show
192.168.234.0/24 dev eth1  proto kernel  scope link  src 192.168.234.146  metric 1
192.168.234.0/24 dev eth2  proto kernel  scope link  src 192.168.234.147  metric 1
192.168.110.0/24 dev eth0  proto kernel  scope link  src 192.168.110.137  metric 1
192.168.110.0/24 dev eth3  proto kernel  scope link  src 192.168.110.135  metric 1
default via 192.168.110.1 dev eth0  proto static

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RHEL6- (9) -ROUTES & DEFAULT GATEWAY – P1


RHEL6-(9)-ROUTES & DEFAULT GATEWAY                               -P1

Under Routes & Default Gateway:

ROUTES & DEFAULT GATEWAY –P1
ROUTES & DEFAULT GATEWAY –P2
ROUTES & DEFAULT GATEWAY –P3

We had already seen about Routes & Gateway before, let’s take in little brief.

Default gateway: A default gateway is a remote host or router that our Linux host forwards traffic to, when the destination IP address of outgoing traffic does not match any route in our local routing table

Static route: Static routes are for traffic that must not, or should not, go through the default gateway.

Default route: If the IP that is to be communicated, does not fall into any of the other routes than send the packets to the default route.

Network Files:
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RHEL6- (8) IP ASSIGN / CHANGE


                 RHEL6- (8) IP ASSIGN/CHANGE

HOW TO ASSIGN/CHANGE THE IP ADDRESS:

[root@rhel6-server ~]# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:0C:29:80:4E:36
          inet6 addr: fe80::20c:29ff:fe80:4e36/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:11151 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1039262 (1014.9 KiB)  TX bytes:468 (468.0 b)

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RHEL6- (7) CHANGE HOSTNAME


     RHEL6-7 CHANGE HOSTNAME:

HOW TO CHANGE HOSTNAME:RHEL6:

[root@rhel6-server ~]# hostname
rhel6-server
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Wednesday 22 February 2017

RHEL-6 (6) KNOW YOUR SYSTEM-P6 (USB)


RHEL-6 (6)
               KNOW YOUR SYSTEM-P6

 Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

USB DRIVE IN LINUX:
How to detect a USB drive in my system?
How to know the usb device name on my system?
How to know which File system is on usb drive?
How to get the usb controller info?
What to do if usb drive is If USB not detecting on my system?
How to mount a usb drive on my system?
How to eject the usb from my system?
How to unmount the usb from my system?
How to format the usb from my system?
How to make the USb drive usable in Windows as well as Linux?
What to do if unable to umount the usb?
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RHEL-6 (5) KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)


RHEL-6 (5)
              KNOW YOUR SYSTEM-P5

Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

CD-DVD ROM:
     How to check the status of CD-ROM in my system?
     How to know the device name of CD-ROM in my system?
     How to know the model name of CD-ROM in my system?
     What is the device format of CD-ROM in my system?
     How to mount CD-ROM in my system?
     How to unmount CD-ROM in my system?
     How to mount ISO image in my system?
     How to unmount ISO image in my system?

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RHEL-6 (4) KNOW YOUR SYSTEM-P4 (NETWORK)


RHEL-6 (4)
               KNOW YOUR SYSTEM-P4

NETWORK:

Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

What is IP/Subnet & gateway of my system?
What is MAC address of my particular Ethernet port?
How to know about the existing routes in system?
How can i make a interface up and down?
How to ping with particular no of counts?
How to trace the route/path of a particular IP?
What are the meanings of different O/P's from traceroute?
How to dump the TCP packets?
What is ARP?
How to add Static ARP Entry on my system?
How to add Static ARP Entries Permanently on my system?
How to delete a Static ARP Entry from my system?
How to print systems routing table?
How to add the route for Host / Network?
How to remove the route?
What are the important files and their descriptions in my system?
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RHEL-6 (3) KNOW YOUR SYSTEM-P3 (DMIDECODE)


RHEL-6 (3)
              KNOW YOUR SYSTEM-P3

Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

How to know about all hardware info of my system in one go?
How to find Server Manufacturer, Model Number, Serial Number?
How to find Processor Information?
How to find Memory information?
How to find Internal Expansion slots information?
How to find the BIOS version?
What is the maximum RAM size supported by the system?
How much RAm system is using?
How to find the available memory slots for expansion?
How to find the serial number without using dmidecode?
Biosdecode
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RHEL-6 (2) KNOW YOUR SYSTEM-P2


RHEL-6 (2)
              KNOW YOUR SYSTEM-P2

Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

How to know about the CPU architecture of my system?
How to know about the Physical Processors in my system?
How to know about the Processor Cores of my system?
How to know about the Virtual Processors of my system?
How to know about the CPU Vendor/Model/Frequency?
How many HDD’s and of what capacity are present in my system?
How to know about the Vendor/model info of attached scsi devices?
How to know about the bad blocks on HDD?
What are the active partitions on my system?
How much free space left on partition?
How to know about the File System Type?
How to know about the utilization of inodes?
How to show the size of a directory?
How to show the files and directories sorted by size?

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RHEL-6 (1) KNOW YOUR SYSTEM-P1


RHEL-6 (1)
                       KNOW YOUR SYSTEM-P1

Under "KNOW YOUR SYSTEM"

RHEL-6 KNOW YOUR SYSTEM-P1
RHEL-6 KNOW YOUR SYSTEM-P2
RHEL-6 KNOW YOUR SYSTEM-P3 (dmidecode)
RHEL-6 KNOW YOUR SYSTEM-P4 (Network)
RHEL-6 KNOW YOUR SYSTEM-P5 (CD/DVD-ROM)
RHEL-6 KNOW YOUR SYSTEM-P6 (USB)

§  What is the name of my system?
§  What is the IP of my system?
§  Which OS installed in my system?
§  What is the kernel version of that OS?
§  What is the release version of OS?
§  How much memory installed in my system?
§  How much swap space specified in my system?
§  How to know only about swap space?
§  When I should be alarmed about memory status?
§  Where the swap is mounted?
§  How to check memory status in real time?
§  How much RAM installed and in which slot?
§  How much Ram my MB can support?
§  How to know the info about PCI devices installed in my system?
§  How to know about the USB devices in my system?
§  How to know about the block devices in my system?

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Saturday 11 February 2017

VERITAS CLUSTER-2 (BASICS)



VERITAS CLUSTER-2

VCS COMPONENTS:


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Thursday 9 February 2017

VERITAS CLUSTER-1 (BASICS)


VERITAS CLUSTER-1

VCS COMPONENTS:

RESOURCES:

As per VCS, A resource is an entity that may be brought online, offline, or monitored on a particular system.

Resource Types:

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Wednesday 8 February 2017

CLUSTER BASICS


                      CLUSTER BASICS

HA……HA………HA……… JJJ ………… It’s not Ha..Ha..Ha LLL

In the world of sys admin the word “HA” is as common as our daily natural activities.                                   

What is this HA…?

HIGH AVAILABILITY………..

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Friday 3 February 2017

LINUX-26 SERVICE MANAGEMENT FRAMEWORK (RHEL-7) [PART-3]


   LINUX-26
    SERVICE MANAGEMENT FRAMEWORK (RHEL-7)
                 SYSTEMD/SYSTEMCTL – PART-3
                                   
We already covered about management of services, targets with systemd in previous posts.

LINUX- 24 SYSTEM MANAGEMENT FRAMEWORK(RHEL-7) PART-1
LINUX- 25 SYSTEM MANAGEMENT FRAMEWORK(RHEL-7) PART-2

# systemctl start [name of service]
# systemctl stop [name of service]
# systemctl restart [name of service]
# systemctl reload [name of service]
# systemctl status [name of service]
# systemctl mask [name of service]
# systemctl unmask [name of service]
# systemctl is-active [name of service]
# systemctl list-units --type service –all

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Thursday 2 February 2017

LINUX-25 SERVICE MANAGEMENT FRAMEWORK (RHEL-7) [PART-2]


   LINUX-25
    SERVICE MANAGEMENT FRAMEWORK (RHEL-7)
                  SYSTEMD/SYSTEMCTL – PART-2
                                   
We learned the basics of init/upstart and little bit of “systemd”.
Now let’s do a brief analysis of SYSTEMD.

In previous post LINUX- 24 SYSTEM MANAGEMENTFRAMEWORK (RHEL-7) PART-1
We were at units and targets in systemd.
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