Wiping hard drive clean in linux

Two good methods of “clearing” your hard drive are: With a Ubuntu or Live CD and in a terminal do this: sudo dd if=/dev/zero of=/dev/XdY or sudo dd if=/dev/random of=/dev/XdY where XdY is the drive, i.e. sda, sdb, or hda, hdb, etc.

Cisco Catalyst 2900/3500/3550 XL Recovery

As per Cisco Catalyst Fixed Configuration Layer 2 and Layer 3 Switches: Unplug the switch. Press the Mode button (left side of front panel) and keep it depressed. Reconnect power. When the LED above Port 1x goes out, release the Mode button. Issue the flash_init command: switch: flash_init Initializing flash… (output deleted…) Issue the load_helper …

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Cisco VPN Client – TCP and UDP Ports

The Cisco VPN client is the client side application used to encrypt traffic from an end user’s computer to the company network. IPSec is used to encrypt the traffic. When using standard IPSec, IKE is used for the key negotiation and IPSec to encrypt the data. IKE uses UDP port 500 and IPSec uses IP …

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Cisco Interface Card WIC-1B-S/T vs WIC-1B-U

The Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) WAN interface cards are used on the Cisco routers. Each card supports a single ISDN BRI port offered with and without the NT1 interface. The S/T WAN interface card module (WIC-1B-S/T) needs the external Network Termination 1 (NT1) device whereas the U WAN interface card module …

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Configuring Cisco router to cable modem

There are 4 basics steps: Set the IP address of the interfaces Set the router as a DHCP server Configure NAT Configure Routing Setting IP Address to Cisco Router’s Interfaces We need to first set the IP address of the router’s interfaces to begin configuring Cisco router to work with cable internet. Make sure your …

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Backup a Cisco router IOS image to pc

!Backup image to TFTP server Router>enable Router#copy flash:{your IOS image filename} tftp://{TFTP server IP address} !Download image from TFTP server Router>enable Router#copy tftp://{TFTP server IP address} flash: Tips * Under any circumstances, DO NOT delete working IOS image off the router flash memory unless the image has been backed up to server (TFTP or FTP …

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Reset Cisco 837,1841 router

Connect to your router with the console port, power on and your router will start booting up and make ctrl-break you will enter in rommon Type the following command : rommon1> confreg 0x2142 rommon2> Cycle the router power … reload the router, it’ll ignore the startup-config After the reload, make a copy run start to …

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Cisco Command Line Interface

Cisco CLI (Command Line Interface) divided into two mode which are USER EXEC MODE and PRIVILEGED EXEC MODE. In user exec mode, all the command are only one time command which when the switch reboot, the setting will disappear and won’t be saved. User will usually goes into this mode when they login. To enter …

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Change Cisco hostname

password : [enter your telnet password here] switch> en password : [enter your privileged exec password here] switch # configure terminal switch (config) # hostname MYSWITCH MYSWITCH (config) # end !Backup your old setup MYSWITCH # copy startup-config startup-config.bak !Save your running setup so it will start at boot MYSWITCH # copy running-config startup-config

Backup cisco configuration file

Password : [your telnet password] switch > enable Password : [your privileged exec password] switch # copy startup-config startup-config.ddmmyyy !note : ddmmyyy is date for better backup archiving.