As you think for your CCNA and CCNP exams, specially if you're effort hands-on training in your bag work or demolition property service, you're feat to be sending a aggregation of pings. As a CCNA or CCNP candidate, you undergo that fivesome vocalization points (!!!!!) as a sound convey indicates that you hit IP connectivity to the far destination. Five periods (.....) indicates that you do not hit that connectivity.
It's not sufficiency to undergo that you don't hit IP connectivity to the far device, you've got to undergo why. Ping is a enthusiastic prototypal travel to meshwork troubleshooting, but the results are quite limited. As a CCNA and CCNP, you've got to undergo how to study the difficulty and hold it. Just hunting at the routing plateau is not sufficiency - a high-powered Cisco debug, debug ip packet, crapper ofttimes exhibit you just where the difficulty is.
WARNING: debug ip boat should not be separate on whatever creation router without discernment the gist of this bidding on your router. This bidding results in a aggregation of production and crapper actually hair up a router.
In this case, we'll separate the bidding on a bag work router that cannot sound 22.2.2.2. The debug module be overturned on and added sound sent.
R1#debug ip packet
IP boat debugging is on
R1#ping 22.2.2.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 22.2.2.2, timeout is 2 seconds:
3d23h: IP: s=1.1.1.1 (local), d=22.2.2.2, len 100, unroutable.
R1#undebug all
All doable debugging has been overturned off
I've altered this production for clarity; the essential word is unroutable. This indicates that the boat is not leaving the router because there is no correct in the routing plateau for this destination. We'll configure a noise choice line and beam the sound again.
R1#ping 22.2.2.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 22.2.2.2, timeout is 2 seconds:
U.U.U
Success evaluate is 0 proportionality (0/5)
That production haw assail those of you who are utilised to effort fivesome of the aforementioned symbolisation backwards whenever you beam a ping. We got threesome Us backwards along with digit periods. We'll today separate debug ip boat and beam the sound again.
R1#debug ip packet
IP boat debugging is on
R1#ping 22.2.2.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 22.2.2.2, timeout is 2 seconds:
3d23h: IP: s=172.12.123.1 (local), d=22.2.2.2 (Serial0), len 100, sending
R1#traceroute 22.2.2.2
Type carelessness ordering to abort.
Tracing the line to 22.2.2.2
1 172.12.123.2 36 msec 36 msec 36 msec
2 172.12.123.2 !H * !H
R1#undebug all
All doable debugging has been overturned off
Again, I've altered this output. The key word in this production is sending, message that the packets are leaving the router. The sound convey of U.U.U is a generalized communication that the packets are indeed existence transmitted, but that a downstream router is having a difficulty routing the packets. Running traceroute reveals whatever more engrossing convey characters! In this case, the downstream router did not hit a correct for the instruction in its routing table.
It's cushy to centre on the topical router when you're not effort constructive sound returns. When troubleshooting this category of issue, ready in nous the difficulty could be on an grey router and not on the topical router. Use debug ip boat to attain trusty the packets are leaving the topical router, and traceroute to watch what downstream router haw hit the problem. And intend utilised to the fact that pings and traceroutes crapper provide you whatever unusual-looking returns!
Chris Bryant, CCIE #12933, is the someone of The Bryant Advantage, bag of liberated CCNA and CCNP tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages.
For a FREE double of his stylish e-books, How To Pass The CCNA and How To Pass The CCNP, meet the website and download your liberated copies. You crapper also intend FREE CCNA and CCNP communicating questions every day! Pass the CCNA communicating with The Bryant Advantage!
