Cisco IOS – cheatsheet

General commands

  • sh ip traffic – all traffic through the Cisco
  • sh controllers ethernet-controller gi1/0/1 phy – information about the SFP module into a particular port
  • show vlan internal usage – used to show vlan
  • sh inventory raw – in 4924 about stuck SFP seems to be the only way to see.
  • sh ip protocols – all of the dynamic routing

Tracing

  • traceroute mac aaaa.bbbb.cccc dddd.eeee.ffff (Traces source and destination mac addresses over multiple switches)

Diagnosing problems with TCAM, ASIC

  • sh platform …
  • sh platform tcam utilization – a place in the TCAM Diagnosing problems with the fallback interface / memory / CPU
  • sh controllers cpu-interface
  • sh controllers utilization – the percentage loading of interfaces. Plus upload the switch factory
  • sh controllers tcam sh controllers tcam asic
  • sh controllers ethernet-controller phy
  • sh controllers ethernet-controller port-asic statistics
  • sh controllers ethernet-controller port-asic configuration
  • sh controllers ethernet-controller gigabitEthernet 1/0/1

Interface Commands show interfaces description

  • show interfaces counters protocol status
  • show interfaces summary
  • show interfaces accounting
  • sh interfaces stats – statistics on the interface, the method of switching
  • sh interfaces switching – a hidden command. More detail than the stats.
  • sh interface switchport – diagnostic vlan
  • show interface trunk – for the diagnosis of vlan
  • show int | i proto.*notconnect|proto.*administratively down|Last in.* [6-9]w|Last in.*[0-9][0-9]w|[0-9]y|disabled|Last input never, output never, output hang never

SDM

  • sh sdm prefer

CDP

  • show cdp neighbors
  • show cdp neighbors detail – here just shows the version of IOS from a neighbor
  • show cdp entry * version – IOS neighbor
  • show cdp entry * protocols – protocols

Multicast

  • sh ip multicast
  • sh ip multicast interface vlan 104
  • sh ip interface vlan 104

PIM troubleshooting

  • sh ip mroute
  • sh ip pim interface
  • sh ip pim rp [mapping]
  • sh ip rpf
  • sh ip pim interface vlan 25
  • sh ip pim neighbor

IGMP troubleshooting

  • sh ip igmp
  • sh ip igmp group
  • sh ip igmp interface ip igmp join-group