1.3.a Use IOS troubleshooting tools

1.3.a [i] debug, conditional debug

there are a massive amount of debugs available from the cli, you simply need to choose the debugs you are interested in using… of course using debugs on a production device might have the unwanted effect of choking traffic, or even crashing the device… so take care…

with conditional debug you have the opportunity of being more specific with the debugging, ie:

R3#debug condition ?
application  Application
called       called number
calling      calling
card         card
glbp         interface group
interface    interface
ip           IP address
mac-address  MAC address
match-list   apply the match-list
standby      interface group
username     username
vcid         VC ID
vlan         vlan

the above is self explanatory…

1.3.a [ii] ping, traceroute with extended options

the history of ping which was created by mike muuss can be found at this link:


van jacobson is credited with co-creating traceroute, as well as varieties of tcp/ip compression and other congestion avoidance mechanisms. ping and traceroute are commonplace, so i’ll just touch on the extended options.

like ping in cisco ios, the extended commands for traceroute are launched by typing traceroute with no arguments:

Protocol [ip]:
Target IP address:
Source address:
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to

1 20 msec 16 msec 24 msec

Protocol [ip]:
Target IP address:
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface:
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/20/24 ms