Synchronizing Router Clock with Network Time Protocol (NTP)
Sep 4th
What is NTP and Why is it used
Network Time Protocol (NTP) was originally developed by David L. Mills of the University of Delaware and is used to synchronize the clocks of the computer system.
NTP uses UDP port number 123, so appropriate firewall configuration or ACL is necessary for it to work properly
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Cisco IOS Tips: Reload Command Explained
Aug 31st
I guess the reload command is self explanatory. It reboots the router.
Reload command can take two different kind of timer
- Execute at specific time or date (e.g at 11:00)
- Execute after certain number of minutes (e.g after 30mins)
Note : The router clock must be set before the reload command can work properly.
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Cisco IOS Tips: Display Interface The Smart Way
Aug 29th
Use the following command to dsplay brief summary of interfaces
Router#show ip int br
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.1.2 YES manual up up
FastEthernet0/1 192.168.10.2 YES manual up up
FastEthernet1/0 unassigned YES unset up down
FastEthernet1/1 unassigned YES unset up down
FastEthernet1/2 unassigned YES unset up down
FastEthernet1/3 unassigned YES unset up down
...
Disable Password Recovery
Aug 26th
There are times when you may want to disable password recovery (for example if someone is working in high secure environment).
Use the following command to disable password recovery
Router(config)#no service password-recovery
WARNING:
Executing this command will disable password recovery mechanism.
Do not execute this command without another plan for
password recovery.
Are you sure you want to continue? [yes/no]: yes
Router(config)#
Cisco Router Password Recovery
Aug 24th
There are times when you need to recover Cisco Router password. This tutorial shows how to do it in few simple and detailed steps. Depending on the router model, the configuration might be slightly different, but the concept remains same (check Summarized Steps)
Although it is possible to bypass router password feature, but it is not possible to recover encrypted passwords. Plain text passwords can be viewed from saved configuration but the encrypted passwords must be changed to a new password.
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Cisco IOS Alias
Aug 15th
Cisco IOS alias can be used to shorten commonly used commands to a command alias.
To save time and the repetition of entering the same command multiple times, you can use a command alias. An alias can be configured to do anything that can be done at the command line, but an alias cannot move between modes, type in passwords, or perform any interactive functions
Cisco DOC
Cisco IOS DHCP Configruration
Aug 11th
Newer Cisco router and switch can act as Dynamic Host Configuration Protocol (DHCP) server.
This article shows how to configure DHCP server and create appropriate address pool for the clients.
Configuration Steps
- Create DHCP pool
- Select address pool for client
- Configure the basic required parameters
- (Optional) Select the address you wish to exclude from the pool
Time Based ACL Configuration
Aug 8th
Time based ACLs were introduced in Cisco IOS 12.0.1.T. They allow for access control based on time.
A time range could be periodic (certain or recurring time of day or week) or absolute (start time to end time). Because time based ACLs rely on router system clock, the router time should be configured properly, either manually or using Network Time Protocol (NTP)
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Basic Connectivity Between Routers
Aug 7th
This tutorial shows how to configure two routers, so they can communicate with each other. It covers the basic of configuring interfaces and checking the connectivity between them.
Let look at the following network diagram.
Configuring Interface
Aug 4th
This short tutorial will show you how to configure an interface in Cisco IOS, assign IP address to it, and then enabling it.
Enter exec mode.
Router>enable Router#
