Stop those translating time

If you do not have DNS enable. You can stop those annoying translating time when you accidentally hit enter when typing anything

configure terminal

no ip domain-lookup

Prefix and Subnet

Number of Usable IP addresses

Prefix	Subnet mask	binary form	Total IPs	Usable IPs
/32	255.255.255.255	11111111.11111111.11111111.11111111	XX	XX
/31	255.255.255.254	11111111.11111111.11111111.11111110	2	XX
/30	255.255.255.252	11111111.11111111.11111111.11111100	4	2
/29	255.255.255.248	11111111.11111111.11111111.11111000	8	6
/28	255.255.255.240	11111111.11111111.11111111.11110000	16	14
/27	255.255.255.224	11111111.11111111.11111111.11100000	32	30
/26	255.255.255.192	11111111.11111111.11111111.11000000	64	62
/25	255.255.255.128	11111111.11111111.11111111.10000000	128	126
/24	255.255.255.0	11111111.11111111.11111111.00000000	256	254
/23	255.255.254.0	11111111.11111111.11111110.00000000	512	510
/22	255.255.252.0	11111111.11111111.11111100.00000000	1024	1022
/21	255.255.248.0	11111111.11111111.11111000.00000000	2048	2046
/20	255.255.240.0	11111111.11111111.11110000.00000000	4096	4094
/19	255.255.224.0	11111111.11111111.11100000.00000000	8192	8190

/18 and so on ... ...

***Subnet mask will begin with series of '1' and end with series of  '0', there will not be combination of '1' between '0' and '0' between '1'.

***Total IPs formula 2 to the power of n where n is equal to the number of '1'

***Usable IPs = Total IPs - 2 (2 IPs is due to network and broadcast address)

Switch Password Reset

Press mode button when powered-up

Screen saying password-recovery mechanism started

flash_init

load_helper

dir flash:

rename flash:config.txt flash:config.bak

boot

no to initial configuration dialog

enable

rename flash:config.bak config.txt

copy flash:config.txt system:running-config

copy running-config startup-config

Reset password

Press break or Control-C when powered-up

in ROMMON

confreg 0x2142

reset

no to System Configuration Dialog

enable

configure memory

copy startup-config running-config

exit

configure terminal

configure-register 0x2102

write memory

Restore back to default

configure terminal

configure-register 0x2142

reload

=>no need to save system config

no to System Configuration Dialog

configure terminal

configure-register 0x2102

write memory

reload

Download the IOS to the rommon

rommon 1 > set 

PS1=rommon ! >  

BSI=0 

RET_2_RUTC=0 

RET_2_RTS= 

?=1  

rommon 2 > IP_ADDRESS=192.168.0.2 

rommon 3 > IP_SUBNET_MASK=255.255.255.0 

rommon 4 > TFTP_SERVER=192.168.0.3 

rommon 5 > TFTP_FILE=c1841-xxxxxx-xx.xxx-xx.xx.bin 

rommon 6 > DEFAULT_GATEWAY=192.168.0.1  

rommon 7 > tftpdnld            

IP_ADDRESS: 192.168.0.2       

IP_SUBNET_MASK: 255.255.255.0      

DEFAULT_GATEWAY: 192.168.0.1          

TFTP_SERVER: 192.168.0.3            

TFTP_FILE: c1841-xxxxxxx-xx.xxx-xx.xx.bin  

Invoke this command for disaster recovery only. 

WARNING: all existing data in all partitions on flash will be lost! 

Do you wish to continue? y/n:  [n]:  y  

Receiving c1841-xxxxxxx-xx.xxx-xx.xx.bin from 192.168.0.3 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

File reception completed. 

Copying file c1841-xxxxxxx-xx.xxx-xx.xx.bin to flash. 

Erasing flash at 0x60fc0000 

program flash location 0x60e70000 

rommon 8 > 

simple OSPF config

configure terminal

Router ospf (process id) e.g. 1

Network (interface ip starting address) (wildcard) area 0

wildcard hint:

0.0.0.0 host address

0.0.0.3 subnet mask : /30 255.255.255.252

0.0.0.7 subnet mask: /29 255.255.255.248

0.0.0.15 subnet mask: /28 255.255.255.240

0.0.0.31 subnet mask: /27 255.255.255.224

0.0.0.63 subnet mask: /26 255.255.255.192

0.0.0.127 subnet mask: /25 255.255.255.128

0.0.0.255 subnet mask: /24 255.255.255.0

Copy the IOS from router to the PC

copy c1841-12-4.xxxx.bin tftp://192.168.0.2

IP address of PC 192.168.0.2

IP address of ethernet interface of router 192.168.0.1

encrypt all password in show run

Service password-encryption

Password encryption is applied to all passwords, including 
1)username passwords
2)authentication key passwords
3)privileged command password
4)console
5)virtual terminal line access passwords
6)Border Gateway Protocol neighbor passwords. 


Keeping unauthorized individuals from viewing your password in your configuration file.

Interface configuration

Cisco


Interface (fa0/0 or s0/0/0 etc… …>)

Description (describe link) =>useful for troubleshooting as it can tell you where is it connected to

Ip address (ip address) (subnet mask)

No shut

hint: subnet mask

/32 255.255.255.255 no useful IP address

/31 255.255.255.254 no useful IP address

/30 255.255.255.252 useful for WAN link, 4 IPs (1 network, 1 broadcast, 2 user IPs)

/29 255.255.255.248 8 IPs (1 network, 1 broadcast, 6 user IPs)

/28 255.255.255.240 16 IPs (1 network, 1 broadcast, 14 user IPs)

/27 255.255.255.224 32 IPs (1 network, 1 broadcast, 30 user IPs)

/26 255.255.255.192 64 IPs (1 network, 1 broadcast, 62 user IPs)

/25 255.255.255.128 128 IPs (1 network, 1 broadcast, 126 user IPs)

/24 255.255.255.0

/23 255.255.254.0

/22 255.255.252.0

/21 255.255.248.0

/20 255.255.240.0


Juniper
Interface (fxp0,lo0,em0,fe-x/0/y,se-x/0/y)
x = PIM slot
y = Port Number


inet => IPv4


root@router#set interfaces em0 unit 0 family inet address (ip address)/(prefix)
root@router#commit


IPv6
Cisco - ipv6 address 2001:db8::1/64
Juniper - set interfaces em0 unit 0 family inet6 address 2001:200:30:2::1/64

Enable Privileged Password Login

Enable secret 5 (Level 2 password)

Cisco's Type 7 scheme is a weak protection scheme.


Type 5 uses a strong, one-way encryption hash (MD5), which will ensure greater security. 


Whenever possible, the Type 5 password protection scheme should be used.

Create username login

Cisco
username (name) password privilege (level) (password)

level 15 (Cisco administrator / super-user access)
level 7 (moderate user access)


Junipers
set system login user (name) classs (class)  authentication plain-text-password



               Login class
  operator             permissions [ clear network reset trace view ]
  read-only            permissions [ view ]
  super-user           permissions [ all ]
  unauthorized         permissions [ none ]

Telnet login using IP address

Cisco


Line vty 0 4

Logging synchronous

Password (level 1 password) =>encrypt password

Login local =>enable password login

Session-limit 1 =>limit to 1 login session

Motd-banner =>display warning message


Juniper


set system services telnet  => enable telnet service on the router
set system login user user1 class super-user authentication plain-text-password


=>You will prompted to set your password


Replace user1 with the username you will like to create
Replace super-user with the level of access right you will like to give to the user

Console Login using rollback cable

Line console 0

Logging synchronous => Information items sent to the console will not interrupt the command you are typing.

Password  7 (level 1 password) =>encrypt password

Login local =>enable password login

Session-limit 1 =>limit to 1 login session
exec-timeout 0 0 => Sets the time limit when the console automatically logs off. Set to 0 0 (minutes seconds) means the console never logs off. Default is 10 minutes.

Hostname

Cisco


Router(config)#Hostname B10_L23_R30
B10_L23_R30(config)#


Juniper



[edit]
root# set system host-name B10_L23_R30


[edit]
root# commit
commit complete


[edit]
root@B10_L23_R30# [edit]

Banner - Warning Message

Cisco


Banner login % (warning message) %

Banner motd % (warning message) %

e.g. 

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*                                                                                                                   *
*                                                                                 *

*    Please navigate away from this website or ip address now if                     *

*    you are not an authorised personnel belonging to ABC Pte Ltd *

*    You will be prosecuted as the host IP that you are using has                    *

*   already been captured by our system if you attempt to navigate                    *

*                                          any further                                           *

*                                                                                 *

*                                                                                 *

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Juniper

Special Characters—You can format the message using the following special characters:

• \n—New line
• \t—Horizontal tab
• \'—Single quotation mark
• \"—Double quotation mark
• \\—Backslash

root@B10_L23_R30# set system login message "\n\n\n\tPlease Do not enter!!!\n\tYou will be prosecuted under the law\n\tPlease contact abc@company.com to gain access.\n\n\n"

e.g.




                Please Do not enter!!!
                You will be prosecuted under the law
                Please contact abc@company.com to gain access.