Cisco IOS

Working with console cables

sudo screen /dev/ttyUSB0 9600

Information

Task	Command
Show IPv4 settings	show ip interface brief
Show IPv6 settings	show ipv6 interface brief
Show routing table	show ip route
Show config	show running-config
Show VLAN (switch) info	show vlan

General configuration

Getting started:

Router>enable
Router#configure terminal
Router(config)#

config-if

Set an IPv6 address:

Router(config)#interface G0/0/0
Router(config-if)#ipv6 address 2001:DB8:0:1::/64
Router(config-if)#ipv6 enable
Router(config-if)#no shutdown
Router(config-if)#exit

Task	Command
Enable crossover cable autodetect	mdix auto

Load config from TFTP server

• enable
• On (some) routers: ip tftp source-interface INTERFACE
• copy tftp run
• Address of remote host: …
• Source filename: …
• Destination filename: running-config

Example:

#copy tftp running-config
Address or name of remote host []? IP_ADDRESS
Source filename []? FILENAME
Destination filename [running-config]? 
Accessing tftp://IP_ADDRESS/FILENAME...
Loading FILENAME from IP_ADRESS (via INTERFACE): !
[OK - 1273 bytes]
...

Routing

IPv4 static routing

Task	Command
Set default GW	ip route 0.0.0.0 0.0.0.0 GW_ADDR
Route to network	ip route NET_ADDR NET_MASK NEXT_HOP

IPv6 static routing

Task	Command
Enable routing	ipv6 unicast-routing
Directly attached static route	ipv6 route 2001:DB8::/32 g1/0/0
Recursive static route	ipv6 route 2001:DB8::/32 2001:DB8:3000:1

Resources:

• https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/configuration/xe-3s/iri-xe-3s-book/ip6-route-static-xe.html
• Example: https://www.cisco.com/c/en/us/support/docs/ip/ip-version-6-ipv6/113361-ipv6-static-routes.html

Enable NAT

• Internal interface (in config-if): ip nat inside
• External interface (in config-if): ip nat outside
• Enable NAT:
  • ip nat inside source list 1 interface G0/0/0 overload
  • access-list 1 permit NET_ADDR WILDCARD, e.g.
    • access-list 1 permit 192.168.0.0 0.0.0.255

Enable DHCP

Router(config)#ip dhcp pool POOL_NAME
Router(dhcp-config)#network NET_ADDR NET_MASK
Router(dhcp-config)#default-router GW_ADDR
Router(dhcp-config)#dns-server DNS_ADDR
Router(dhcp-config)#ip dhcp excluded-address START END

• Set tftp server: option 150 ip TFTP_ADDR

Switch

• Useful commands
  • show ip int br
  • show ip ? -> shows possible expansions of an incomplete command
• Assigning an IP address to a switch
  • interface vlan 1
  • ip address 192.168.200.13 225.225.225.248
  • no shutdown
  • end
• Reset to defaults (assuming no persistent configuration):
  • delete flash:vlan.dat: VLAN-settings verwijderen
  • erase startup-config: alle manuele instellingen verwijderen
  • reload