Debug - jibingl/CCNA-CCNP GitHub Wiki

📢 To observing debug messages, logging must be enabled at debugging level (level 7).

! Check logging message level
R1# show logging

! Enable debug for all or specific 
R1# debug all

! Set the console logging of messages at debugging level (level 7)
R1# logging console debugging

! Display enabled debugs
R1# show debug
  • Logging messages (including debug) are sent to console by default regardless. So, too much debug output can freeze the device.
  • To limit debug messages output, use conditional debug or combine with ACL.
! Specify a condition for debug
R1# debug condition interface g0/0

! Debugging with an ACL 110
R1# debug ip packet 110
  • undebug all DO NOT remove debugging conditions but only disable debugs. The conditions will be applied to future debugs.
! Disable debug
R1# undebug all
! Or
R1# no debug

! Remove debug conditions
R1# undebug condition all
! Or
R1# no debug condition all