Forgot the root password for my RedHat Enterprise Linux 5 Server

ខ្ញុំបានដំឡើង RedHat Enterprise Linux 5 នៅក្នុង VMware Workstation មួយសន្ទុះក្រោយមកបានភ្លេចលេខសំងាត់របស់ root។ ខ្ញុំអាច Login ជា user ធម្មតាបាន ប៉ុន្តែវាគ្មានសិទ្ធិក្នុងការកែប្រែនោះទេ។ ខាងក្រោមនេះខ្ញុំនិងធ្វើការបង្ហាញនូវការផ្លាស់ប្តូរ password របស់ root:

To enter single user mode, reboot the server. When you see the RedHat Enterprise Linux 5 splash screen, press any key to enter the boot menu.


Press 'e' key to edit the commands before booting

កម្មវិធី SolarWinds - Advanced Subnet Calculator

SolarWinds Advanced Subnet Calculator is completely free and fully functional. In fact, it actually delivers four tools in one:

What is Trivial File Transfer Protocol (TFTP)

Trivial File Transfer Protocol (TFTP) is a file transfer protocol, which is the basic form of File Transfer Protocol (FTP). Trivial File Transfer Protocol (TFTP) has a very simple design and it requires only a very small amount of memory. Trivial File Transfer Protocol (TFTP) is mainly used for network booting of computers and network infrastucture devices such as routers and switches. Trivial File Transfer Protocol (TFTP) is used in Cisco networking environment to back up IOS, configuration files, and for an IOS upgrade.

Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol and it is implemented on top of the User Datagram Protocol (UDP). The standard UDP port number for Trivial File Transfer Protocol (TFTP) is 69.

Cisco Router Show Commands

 The show commands are very useful Cisco IOS commands. The Cisco Router show commands can be used to examine nearly everything about a router and its configuration. Following table lists important Cisco Router Show Commands and use.
  

Command	Description
Router#show interfaces	Displays statistics for all interfaces
Router#show interface e0	Displays statistics of e0 interface. You may use other interface also.
Router#show ip interface brief	Displays a summary of all interfaces, including status and IP address assigned
Router#show controllers serial 0	Displays statistics for interface hardware. Statistics display if the clock rate is set and if the cable is DCE, DTE, or not attached
Router#show clock	Displays the router clock.
Router#show hosts	Displays local host-to-IP address addresses of hosts on the network to which you can connect
Router#show users	Displays all users connected to device
Router#show history	Displays history of commands used
Router#show flash	Displays info about Flash memory
Router#show version	Displays info about loaded software
Router#show arp	Displays the ARP table
Router#show protocols	Displays status of configured Layer 3 protocols
Router#show startup-config	Displays configuration saved in NVRAM
Router#show running-config	Displays configuration currently running in RAM

Enjoy...!

Basic Cisco Router Configuration Commands

How to Configure a Router Hostname
To configure a name for router, use hostname command for Global Configuration mode.

 Router>enable

 Router#configure terminal

 Router(config)#hostname hour4khmer.R1

 hour4khmer.R1(config)#exit

 hour4khmer.R1#

VanDyke SecureCRT v6.7.1 build 188

SecureCRT is an extremely customizable terminal emulator for internet and intranet use with support for Secure Shell (SSH1 and SSH2) as well as Telnet and RLogin protocols. SecureCRT is ideal for connecting to remote systems running Windows, UNIX, and VMS. SesureCRT support secure file transfers via Xmodem, Zmodem, and SFTP.

របៀបតំឡើង អ៊ិនធើណិត(Internet) ដោយប្រើប្រាស់ Cisco Router 1800 Series

តាមរូបខាងលើឃើញថា ក្រុមហ៊ុន ISP បានផ្តល់នូវ IP Address, Subnet Mask, Default Gateway, DNS។ យើងនិងធ្វើការកំណត់នូវ IP Address ទៅអោយ Router ដូចរូបភាពខាងក្រោម

TeamViewer (All-In-One Solution for Remote Access and Support over the Internet)

TeamViewer connects to any PC or server around the world within a few seconds. You can remote control your partner's PC as if you were sitting right in front of it.

Website: www.teamviewer.com

How to enable SSH (Secure Shell) on Router

SSH (stands for "Secure Shell) is  the protocol the campus IT department wants you to use for  command-line (or shell) access to a campus Unix server.  (For those of you who know the term "telnet", SSH is a newer, more secure, replacement for it — when you login to a server, telnet transmits your password in the clear over any intervening network; SSH encrypts it.)   The SSH protocol is provided by a variety of freeware or commercial software products. IT has installed a freeware version of an SSH client on most (all?) public Windows machines in campus labs and its license permits students and faculty to download and install it for personal use at home. 

GNS3 Graphical Network Simulator

GNS3 is a graphical network simulator that allows simulation of complex networks.

To allow complete simulations, GNS3 is strongly linked with :

• Dynamips, the core program that allows Cisco IOS emulation.
• Dynagen, a text-based front-end for Dynamips.
• Qemu, a generic and open source machine emulator and virtualizer.

SolarWinds Engineers Toolset

Network troubleshooting is easy when you have the right network tools! Engineer’s Toolset delivers an advanced collection of must-have monitoring, discovery, diagnostic, and Cisco tools. Discover why thousands of network engineers rely on Engineer’s Toolset!