Entries for the ‘Tutorial’ Category

Hub & Spoke: an example of VRF-Lite

VRF is an extension of IP routing that provides multiple routing instances. It provides a separate IP routing and forwarding table to each VPN and is used in concert with MP-iBGP (Multi-Protocol internal BGP) between provider equipment (PE) routers to provide Layer 3 MPLS-VPN. However, ML-Series VRF implementation is without MP-iBGP. With VRF Lite, the [...]

Smartports Macros: a useful command

Working in a datacenter, it is often required to apply the same intereface configuration on many ports; Cisco has an embedded useful command to do it: the smartports macros.
Smartports macros provide a convenient way to save and share common configurations. You can use Smartports macros to enable features and settings based on the location of a switch [...]

How to use archive command to save configuration

In a large/critical network, it is fundamental backup the Cisco configuration for two reasons:

Rollback configuration
Restore configuration in case of a broken router

There are two ways to backup: manually (using write command each time that you would save running configuration) or automatically (using software like Ciscoworks, HP OpenView, … ).
In this tutorial, I would explain a different [...]

Slow ADSL with 12.4 IOS version?!

Recently, I have upgraded my Cisco 2650XM from 12.3 to 12.4 version; I use it to connect my PC to Internet, but something goes wrong.
After the upgrading, I have tried to downlad an ISO image but the speed was very low (about 300KB/s and not 700KB/s). Mhhh this is strange! I have begun the troubleshooting [...]

How to create shortcut command

Cisco IOS permits to define a shortcut to complex command. 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.
To create a command alias, issue the alias command in global configuration mode. The syntax [...]

CoPP?! What is that?

Cisco Network Foundation Protection (NFP) is an umbrella strategy encompassing Cisco IOS Security features that provides the tools, technologies, and services that enable organizations to secure their network foundations. NFP helps to establish a methodical approach to protecting router planes, forming the foundation for continuous service delivery.
The router is typically segmented into three planes of [...]

OSPF Virtual Link

The Open Shortest Path First (OSPF) protocol, defined in RFC 2328, is an Interior Gateway Protocol used to distribute routing information within a single Autonomous System.
The OSPF protocol is based on link-state technology, which is a departure from the Bellman-Ford vector based algorithms used in traditional Internet routing protocols such as RIP. OSPF has introduced [...]

Have you never seen a Cisco crash?

It is not common see a Cisco crash: Software forced crash, Bus Error, Software watchdog timeout, and so on…
But if you would do it, there is a pretty trick : it’s the “test crash” command, an hidden IOS command. This can help you if you are lucky enough to have the real crash [...]

BGP best path selection

The Border Gateway Protocol (BGP) is an interautonomous system routing protocol. An autonomous system is a network or group of networks under a common administration and with common routing policies. BGP is used to exchange routing information for the Internet and is the protocol used between Internet service providers (ISP).
BGP is used between autonomous systems [...]

Tips for securing Cisco administrative access

In this article I would explain some tips for securing Cisco administrative access.
When creating passwords, keep these rules in mind:

Make passwords lengthy
Passwords should combine letters, numbers, and symbols. Passwords should not use dictionary words
Change passwords as often as possible

Strong passwords are the primary defense against unauthorized access to your router. The best way to manage [...]