====== Initial Switch Configuration ====== Let's jump straight in. Damn table of contents bar makes this look goofy... ===== Setting Hostname ===== ---- The hostname makes the device easy to identify, especially in large network diagrams. Starting from User EXEC mode (''**Switch>**'') issue ''**enable**'' to enter Privileged EXEC mode followed by ''**configure terminal**'' to enter Global Config mode. Set your hostname with ''**hostname YourNameHere**''. Voila! Switch>enable Switch#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#hostname TheBigOne TheBigOne(config)# From this point forward shortened commands will be used. They're standard practice, so get used to seeing them. ===== Passwording Privileged EXEC ===== ---- The first (not so secure) way to do this is with the ''**enable password PASSWORD**'' command. While this command does set a password on our Privileged EXEC, it does so in clear text. The command and the password you supplied are clearly visible in the output of ''**show run**''. Running ''**service password-encryption**'' from Global Config mode will perform basic obfuscation on all? clear-text passwords configured on the device. TheBigOne>en TheBigOne#conf t TheBigOne(config)#enable password cisco The preferred method is to use the ''**enable secret PASSWORD**'' command. The difference between using ''**secret**'' and ''**password**'' is that secret encrypts the password immediately. In the event that ''**enable password**'' //AND// ''**enable secret**'' are both configured on the device, the password supplied with ''**enable secret**'' will supercede the password supplied with ''**enable password**''. TheBigOne>en TheBigOne#conf t TheBigOne(config)#enable secret cisco ===== MOTD Banner ===== ---- Sets a 'Message of the Day' banner. Configure with the ''**banner motd %Your message goes here!!!%**'' command. A thing to note with this command is the first and last characters after ''**motd**'' are delimiting characters. In the example I used the ''%'' character. Your banner will begin and end with that same character. TheBigOne>en TheBigOne#conf t Enter configuration commands, one per line. End with CNTL/Z. TheBigOne(config)#banner motd %Surely this is a very important message. BE SURE TO READ!!!% ^ ^ **** logging into the device after the banner is set **** Surely this is a very important message. BE SURE TO READ!!! TheBigOne> ===== Telnet / SSH and Configuring an IP Address ===== ---- Remote administration is popular, allowing users from abroad to make changes when needed without having to gain console access with a rollover cable. Remote access is done with either Telnet (NOT SECURE) or SSH. We not only need to configure the device to accept Telnet or SSH traffic, we also need to give the switch an IP address from which to transmit and receive said traffic. \\ \\ \\ **IP Address on interface VLAN 1:** Switch>en Switch#conf t Switch(config)#int vlan 1 Switch(config-if)#ip address 1.1.1.1 255.255.255.0 Switch(config-if)#no shut %LINK-5-CHANGED: Interface Vlan1, changed state to up ** Telnet: ** If you don't set a password on Privileged EXEC you'll be stuck in User EXEC mode (ewww). Things to note: * ''**login**'' command requires remote user to authenticate with the password set on the vty console. * If ''**login**'' is not set, the user gets free access to the device. * Telnet transmits in clear text. Use only when you have nothing to lose (home labs and such). Switch#en Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#enable secret cisco Switch(config)#line vty 0 15 Switch(config-line)#password telnet ** SSH: ** A few more steps involved: * Create a user on the device with ''**username**'' * On vty lines: set login to use local username / password with ''**login local**'' * This option bypasses the password set under the vty lines with the username's password. * Set a domain name: (required to generate RSA keys used for SSH security): ''**ip domain-name //example.com//**'' * Generate RSA keys: ''**crypto key generate rsa**'' MySwitch(config)#username caborym secret cats MySwitch(config)#line vty 0 15 MySwitch(config-line)#login local MySwitch(config-line)#exit MySwitch(config)#ip domain-name example.com MySwitch(config)#crypto key generate rsa The name for the keys will be: MySwitch.example.com Choose the size of the key modulus in the range of 360 to 2048 for your General Purpose Keys. Choosing a key modulus greater than 512 may take a few minutes. How many bits in the modulus [512]: % Generating 512 bit RSA keys, keys will be non-exportable...[OK] *Mar 1 0:29:49.189: RSA key size needs to be at least 768 bits for ssh version 2 *Mar 1 0:29:49.189: %SSH-5-ENABLED: SSH 1.5 has been enabled ===== Speed / Duplex ===== ---- Speed and Duplex are auto-negotiated by default. These commands also work on routers. Manually configure them with: Switch(config-if)#speed ? 10 Force 10 Mbps operation 100 Force 100 Mbps operation auto Enable AUTO speed configuration Switch(config-if)#duplex ? auto Enable AUTO duplex configuration full Force full duplex operation half Force half-duplex operation Re-enable auto-negotiation by removing the configured speed/duplex: Switch(config-if)#no duplex Switch(config-if)#no speed