Use of the Cisco device debug command

Some common debug commands are listed below. More specific debug commands related to various protocols and functions are described below.
For more information, see the relevant sections in this manual and command reference manual. To use the debug function, you must
Configure in user mode:
Command function
Switch # debug displays all available debug commands and short
Description
Switch # show debugging: displays the status of each debug Switch.
Switch # debug all turn on all debugging switches OF THE SYSTEM
Switch # undebug all turn off all debugging Switches
Switch # debug aaa turn on the AAA debugging Switch
Switch # debug acl enable ACL debugging
Switch # debug arp turn on ARP debugging Switch
Switch # debug dvmrp turn on the dvmrp debugging Switch
Switch # debug filter turn on the filter debugging Switch
Switch # debug igmp turn on IGMP debug Switch
Switch # debug ip enable IP address debugging
Switch # debug mstp enable the MSTP debugging Switch
Switch # debug multicast enable the multicast data stream debugging Switch
Switch # debug pim enable the PIM debugging Switch
Switch # debug sys-guard turn on the sys-guard debug Switch
Switch # debug vlan enable VLAN debugging
First, enable the log function:
Switch (config) # logging on,
Second, set the log level to Debug:
Switch (config) # logging monitor 7
In Telnet Client Login mode, the default debug debugging information is not sent to the Telnet client. to display the debugging information on the Telnet client, you must use the privileged user mode of the terminal session, run the following command:
Switch # terminal monitor
The vswitch contains a large number of Debugging commands. The above table lists only the first-level commands of DEBUG.
There are many DEBUG commands with their own sub-commands, such as the debug ip command, and there are many extension options
Item:
Switch # debug ip
Cache Debug IP cache
Ospf Debug IP OSPF
Packet Debug IP packet
Packet-event Debug IP packet-event
Rip Debug IP RIP
Note:
When the debug switch is enabled, CPU resources will be used up. Some debugging switches are turned on, which may even seriously occupy CPU resources.
Switch operation efficiency, so do not enable the debug switch easily if necessary, especially with caution
After debugging, you should disable all debugging switches.