====== Cisco IOS primer ======

Written as a really basic intro to Cisco Ethernet Switches.

Cisco Ethernet switches are referred to as "Managed", this means they can be programmed to control how they behave and also can be interrogated to determine the status and give any warnings about faults.


Example of an unmanaged switch intended for home or small office use. Limited number of ports.
{{networking:unmanagedwitch.jpg?200|Unmanaged switch}} \\


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{{ networking:managedswitch-3750.jpg?200|Managed Cisco switch}} \\
Example of a Cisco Managed Switch, this has 24 copper ports and two fibre ports intended to link to other switches in the "core" of the network. Aimed at more commercial usage, but if you can find somewhere out of earshot (due to fan noise) for it to live, very reliable for home use too. Cheap off Ebay 2nd hand too. Don't use an enclosed cupboard as eventually they will get too hot without ventilation.



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{{networking:consoleport.jpg?200 |Cisco console connections}} \\
On a managed switch, you need to be able to access some sort of interface to control the switch, this is done via a serial port connection initially and then when the switch has an ip address allocated, it can be accessed over the network with either ssh or telnet.
In the picture, there ports bounded by blue are the console ports. There is a rj45 for serial and a USB which emulates a serial port. Using this avoids having to use an external usb to serial converter if your computer does not have a serial port. The four yellow ports at the bottom are for fibre modules ([[rb:sfp|sfp]]) to connect to, the yellow rj45 at the top is for connecting to a management ethernet network.

===== Config =====


On first boot via the console connection (serial 9600 Baud, 8N1), you will be in "User Exec" level, so the commands here will be to view information only, to see sensitive information or change settings, you need to "Enable"  "privileged Exec" level, the command for this is ''enable'', shortened to ''en'', with all commands ''?'' will show possible completions and ''tab'' will complete as much of the command as it can, if something is ambiguous, it will complete as much as it can.

This link from Cisco gives a high level overview:- [[https://www.cisco.com/E-Learning/bulk/public/tac/cim/cib/using_cisco_ios_software/02_cisco_ios_hierarchy.htm]]



===== Examples =====

Console login with no passwords set

<code>
switch> en    <------ User exec prompt ">"
switch#       <------ Privileged exec prompt "#"

switch# exit  <------ exit back to user exec
switch>

</code>

Network login with passwords

<code>
user@x200:~$ ssh -l admin 192.168.1.2  <---- ssh for newer kit, telnet for older
Password: 

2960-1>

2960-1>en
Password: 
2960-1#

2960-1# exit
2960-1> exit
Connection to 192.168.1.2 closed by remote host.
Connection to 192.168.1.2 closed.
user@x200:~$ 
</code>


Showing the current config, this is called the ''running config'', the ''startup config'' is loaded from flash at boot time
<code>
2960-1#sh run   <----------- Abbreviation of ''show running config'', tab will expand
Building configuration...

Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname c3548
!
!
interface FastEthernet0/1
 description EGM port

</code>

Setting the device ipaddress and configuring an interface

<code>
2960-1# conf t  <------- short for Configure Terminal

2960-1(config)#interface vlan 1
2960-1(config-if)#ip address 192.168.1.251 255.255.255.0
2960-1(config-if)#

2960-1(config-if)#exit
2960-1(config)#exit
2960-1#
00:07:57: %SYS-5-CONFIG_I: Configured from console by consolecopy runn


2960-1#copy running-config start     <-------- tab expands this to startup-config
2960-1#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]
2960-1#


2960-1# conf t  <------- short for Configure Terminal

2960-1(config)#interface FastEthernet0/1
 description Link to router
 exit
2960-1# 

</code>



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