switching Archives : FATMIN

First off let me say that its really good practice to configure ports one by one, at least when you are starting out in the network world, as the repetition of typing the same thing over and over helps you to remember the proper commands. Hell this is one of the reasons that I blog the stuff that I do… I'm trying to make sure that I do not forget what I just learned.

Anyway, this is a quick and dirty one that I cannot remember to save my life. In this instance I wanted to configure a few ports on a 2950 that I plan to use to replace my 2960, as my 2960 is destined for bigger and better things given its layer 3 capabilities.

Note the spaces between the first port in the range, the dash, and the last port in the range.

s-2950-1.localdomain(config)#interface range fastEthernet 0/9 – 16
s-2950-1.loc(config-if-range)#description vlan 1 ports
s-2950-1.loc(config-if-range)#switchport mode access
s-2950-1.loc(config-if-range)#switchport access vlan 1
s-2950-1.loc(config-if-range)#spanning-tree portfast

%Warning: portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc… to this
interface when portfast is enabled, can cause temporary bridging loops.
Use with CAUTION

%Portfast will be configured in 8 interfaces due to the range command
but will only have effect when the interfaces are in a non-trunking mode.

s-2950-1.loc(config-if-range)#spanning-tree bpduguard enable
s-2950-1.loc(config-if-range)#end
s-2950-1.localdomain#copy run start

HomeLab: Simple SSH Setup on a Cisco Router

HomeLab: Cisco 2621 Router Password Recovery/Factory Reset

HomeLab: Cisco 3550 Switch Software Configuration Guide

MDH Lab – Securing STP

EIGRP (Enhanced Interior Gateway Routing Protocol), is a Cisco proprietary routing protocol (until recently). When a router runs EIGRP, it keeps a copy of its neighbors routing table. If I router cannot find a route it its, or its neighbor's routing table, it will query its neighbors who in turn query their neighbors.

Exactly how routing protocols work is serious business, but dont worry we are not going to go into that here. Below is the process that I used to setup EIGRP on a Cisco 2811.

Before we do anything, lets get into Configuration mode (conf t).

r-2811-1#conf t

Your first step is going to be to enable IP Routing on your device. But before you do so, make sure that you have configured a Gateway of Last Restort. I did not and had to hook up the old console cable.

The IP of this router is 10.1.0.2, and its directly connected to 10.1.0.1, which is its last resort first hop, so lets configure that .

r-2811-1(config)#ip route 0.0.0.0 0.0.0.0 10.1.0.1

Ok so now lets enable IP Routing

r-2811-1(config)#ip routing

Now lets start EIGRP and chose an AS number. Note that I used 10 on the other three routers in my setup so thats what we are going to use here.

r-2811-1(config)#router eigrp 10

Now we need to tell the router what networks are connected to it (or in this case, will be connected to it). This is the information that the router will share with its neighbors.