Debugging can provide important information to a network engineer when troubleshooting an issue. One of the important reasons for enabling debugging is to check at a deeper level why something is not working as it should be.
Debugging can sometimes be too informational, so access lists can be used on some debug commands to restrict the output, for example with
debug ip packet <access-list>. Some debugging features allow it to be restricted to an interface rather than all interfaces on a network device.