New Cisco CCNP Routing & Switching 2014

Cisco announced major revisions to the Cisco CCNP (Certified Network Professional) Routing and Switching certification at the end of July. All three courses: Implementing Cisco IP Routing (ROUTE), Implementing Cisco IP Switched Networks (SWITCH) and Troubleshooting and Maintaining Cisco IP Networks…
VLAN vs. Subnet

“What is the difference between a subnet and a vlan? How does a subnet and vlan work differently from each other?” “While going through the CCNP switch book of CISCO, I encountered this statement “The switch port supports one VLAN,…
Show ip route

To display the current state of the routing table, use the show ip route command in user EXEC or privileged EXEC mode. The show ip route command is a powerful tool to use at this point in your search. You…
Show processes memory

The show memory exec command is often used to check the amount of a router’s free memory. In troubleshooting cases where router performance is the focus, this is a major command used to see the statistics about the router’s memory. To show…
Configure logging in Cisco IOS

Knowing how to properly use logging is a necessary skill for any network administrator, and the Cisco IOS offers many options for logging. Logging can use for fault notification, network forensics, and security auditing. Cisco routers log messages can handle…
Show module command

Show modules: To display the module status and information, use the show module command in user EXEC or privileged EXEC mode. This example shows how to display information for all modules on a Catalyst 6500 series switch that is configured…
Show interfaces

Show interfaces: Use the show interfaces EXEC command to display statistics for all interfaces configured on the router or access server. The resulting output varies, depending on the network for which an interface has been configured. show interfaces [type number]…
Show running-config

Show running-config: To display the configuration information currently running on the terminal, use the show running-config EXEC command. This command replaces the write terminal command. Syntax Description: This command has no arguments or keywords. Command Mode: EXEC Usage Guidelines This…
Cisco Show Version Command

Show version: Displays information about the router’s internal components, including the IOS version, memory, configuration register information, etc. The most common use of the show version command is to determine which version of the Cisco IOS a device is running.…
Cisco Show Stacks Command

Show stacks is an exec command that is commonly used to diagnose system crash situations. The first section of this command’s output displays stack utilization of processes and interrupt routines, and the reason for the last system reboot. When a system…

DHCP snooping is a security feature intended to prevent rogue DHCP server from sending malicious DHCP replies. When DHCP snooping is enabled, the switch intercept all the DHCP requests, and discards DHCP replies coming from “untrusted” ports. The offending switch…
How to Troubleshoot OSPF?

OSPF is one of our more complicated routing protocols, and it can be pretty intimidating, especially at first. But once you have mastered how to configure this Link State Protocol, the first thing you realize is that it is built…