How to Upgrade the IOS of a Router

Please Follow the below given steps to Upgrade the IOS of a Router.

•          Connect Consol cable to Router.

•          Give IP address 192.168.1.1 to Fast Ethernet interface.

•          Enable Telnet in Router.

•          Give the same range IP address to Computer (192.168.1.2)

•          Install TFTP on Computer.

•          Connect Cross cable to Router Fast Ethernet interface.

•          Ping Router IP from PC.

•          Click on TFTP.EXE

•          It will automatically take the IP address of that computer.

•          Telnet the Router.

•          Type “Show flash” .

•          Select the IOS File name.

•          Type “copy flash tftp” to take the backup of current IOS.

•          Give the IP address of Remote computer.

•          Give the source & destination file name.

•          Type “Delete c1841-Lank9.12.3.222.bin” to delete the old IOS from the router.

•          Press enter key once more to confirm deletion of IOS.

•          Type “copy tftp flash”

•          Give the IP address of Remote computer.

•          Give the source & destination file name.

•          Reboot the router

•          In Configuration Mode type “Boot system flash”

•          Type “show flash” to confirm.

How to Break Router's Password

Please Follow the Below given Steps to Break Router’s Password

•          Reboot the Cisco Router.

•          Press Ctrl key & Break Key together.

•          It will come on Rommon Mode Exp:-(Rommon>)

•          Type “Confreg” to check configuration register value.

•          It will show (0x2102)

•          Change it to “ Confreg 0x2142” press enter.

•          Type “I” for initialization.

•          Reboot the Cisco Router.

•          It will ask you “ Would you like to enter in auto configuration mode? (Y/N): N

•          It will come to “Router>”

•          Go in configuration mode & change the configuration Register value to same as previous.

How Internet Begin

How Internet Begin:

In 1957 United States formed the Advanced Research Project Agency (ARPA) within the Department of Defense (DOD) to lead the Military in Science & technology.

In 1962, Paul Baran was commissioned by the U.S Air Force to develop a method that would enable the U.S to maintain control over it’s military even after a Nuclear Attack. The final Proposal was to implement a Packet Switched Network.

*Important Note: Packet Switching breaks down data that travels over the network into small Packets. These Packets reach to the destination computer with the Direct Path or Alternative Path.

Stage 1: ARPANET -> In 1968, Bolt, Beranak & Newman [BBN] was contracted by ARPA to build this Packet Switching Network known as ARPANET.

There were four sites that were initially connected.

1. University of California at Los Angeles
2. Standford Research Institute
3. University of California at Santa Barbara
4. University of Uthah

The Network was wired together using 50 KBPS circuits and was managed by Information Message Processors [IMP] that run on Honeywell 516 minicomputers. The Protocol used to communicate between Host was the (NCP) Network Control Protocol, Which enabled host running on the same network to transfer data.

*Important Note: A Protocol is an agreement used for communication between two network Hosts. The Protocol defines how data should be packaged for transmission on the network so the receiving host can unpackage it on the receiving end.

By 1972, Ray Tomlinson created an email Program that enables a user to send personal message across the network. The ARPA was renamed DARPA.

In 1973, A Development began on the protocol suite is now known as TCP/IP Protocol Suite. Vinton Cerf & Bob Kalm from DARPA headed this Development.

In 1976, Two Major Networking developments occurred. BOB Metcalfe of Xerox developed Ethernet, Which allowed for the development of Local Area Networks. The other major Development was the Implementation of SATNET the Atlantic Packet Satellite network that linked the United States with Europe.

By 1983, The ARPANET had been split into the ARPANET & the MILNET (Military Network). This Separated the Public Portion of the ARPANET from the Military Component. The Year 1983 was also a cut off for use of NCP on the ARPANET. All Participating networks had to switch to TCP/IP Network.

As a Result of increase in participants on ARPANET & MILNET, The University of Wisconsin Introduced a better Name Resolution DNS – Domain Name Space

End Point Security Control Configuration in Cisco Switches

Implementation step for end point protections:

 a)   Command to be applied on L2switch

Switch# config t

spanning-tree portfast bpduguard default

errdisable recovery cause all

errdisable recovery interval 30

b)   Command to be applied on access ports of switch except critical devices, Uplinks and Trunk Ports.

interface GigabitEthernet< interface number>

switchport mode access

switchport access vlan

logging event link-status

spanning-tree portfast

spanning-tree bpduguard enable

switchport port-security

switchport port-security maximum 1

Rollback step for end point protections:

a)   Command to be applied on L2switch

switch# config t

no spanning-tree portfast bpduguard default

no errdisable recovery cause all

no errdisable recovery interval 30

b)   Command to be applied on access ports of switch except critical devices, Uplinks and trunk Ports.

interface GigabitEthernet< interface number>

logging event link-status

no spanning-tree portfast

no spanning-tree bpduguard enable

no switchport port-security

no switchport port-security maximum 1

All Three Classes(A,B,C) Subnets

Class A Subnets
Subnet Mask	Networking Bits	Number of Networks	Number of Hosts
255.255.255.252	/30	4,194,304	2
255.255.255.248	/29	2,097,152	6
255.255.255.240	/28	1,048,576	14
255.255.255.224	/27	524,288	30
255.255.255.192	/26	262,144	62
255.255.255.128	/25	131,072	126
255.255.255.0	/24	65,536	254
255.255.254.0	/23	32,768	510
255.255.252.0	/22	16,384	1,022
255.255.248.0	/21	8,192	2,046
255.255.240.0	/20	4,096	4,094
255.255.224.0	/19	2,048	8,190
255.255.192.0	/18	1,024	16,382
255.255.128.0	/17	512	32,766
255.255.0.0	/16	256	65,534
255.254.0.0	/15	128	131,070
255.252.0.0	/14	64	262,142
255.248.0.0	/13	32	524,286
255.240.0.0	/12	16	1,048,574
255.224.0.0	/11	8	2,097,150
255.192.0.0	/10	4	4,194,302
255.128.0.0	/9	2	8,388,606
255.0.0.0	/8	1	16,777,216

Class B Subnets
Subnet Mask	Networking Bits	Number of Networks	Number of Hosts
255.255.255.252	/30	32,768	2
255.255.255.248	/29	8,192	6
255.255.255.240	/28	4,096	14
255.255.255.224	/27	2,048	30
255.255.255.192	/26	1,024	62
255.255.255.128	/25	512	126
255.255.255.0	/24	256	254
255.255.254.0	/23	128	510
255.255.252.0	/22	64	1,022
255.255.248.0	/21	32	2,046
255.255.240.0	/20	16	4,094
255.255.224.0	/19	8	8,190
255.255.192.0	/18	4	16,382
255.255.128.0	/17	2	32,764
255.255.0.0	/16	1	65,534

Class C Subnets
Subnet Mask	Networking Bits	Number of Networks	Number of Hosts
255.255.255.252	/30	64	2
255.255.255.248	/29	32	6
255.255.255.240	/28	16	14
255.255.255.224	/27	8	30
255.255.255.192	/26	4	62
255.255.255.128	/25	2	126
255.255.255.0	/24	1	254

Powers of 2(IP Addressing & Subnetting)

Powers of 2
21 = 2	29 = 512	217 = 131,072	225 = 33,554,432
22 = 4	210 =1,024	218 = 262,144	226 = 67,108,864
23 = 8	211 = 2,048	219 = 524,288	227 = 134,217,728
24 = 16	212 = 4,096	220 = 1,048,576	228 = 268,435,456
25 = 32	213 = 8,192	221 = 2,097,152	229 = 536,870,912
26 = 64	214 =16,384	222 = 4,194,304	230 = 1,073,741,824
27 = 128	215 = 32,768	223 = 8,388,608	231 = 2,147,483,648
28 = 256	216 = 65,536	224 = 16,777,216	232 = 4,294,967,296

Binary to Decimal to Hexadecimal Conversion for Bit Values

Decimal	Binary	Hexadecimal
0	0000	0
1	0001	1
2	0010	2
3	0011	3
4	0100	4
5	0101	5
6	0110	6
7	0111	7
8	1000	8
9	1001	9
10	1010	A
11	1011	B
12	1100	C
13	1101	D
14	1110	E
15	1111	F