ICND1 break down — Pings and extended pings

Posted on July 15, 2009. Filed under: CCNA, ICND1 break down | Tags: , , , |


The video talk about ping and extended ping:

The normal ping command,

Router#ping 10.0.0.0

allows us to trouble shooting routing problems.

On Cisco routers, we could get any of the following ping results:

  • !!!!! — IP connectivity to destination exists.
  • ….. — IP connectivity to destination doesn’t exist.
  • U.U.U — The local router has a route to the destination, but the downstream router doesn’t have a route.
  • C.C.C — congestion
  • ?.?.? — unknown packet type
  • &.&.& — packet lifetime exceeded

The usefullness of ping is magnified by command “debug ip packet”.

When an IP address can be ping through, the “debug ip packet” results in the following output:

IP: s=172.12.123.3 (local), d=172.12.123.2 (Serial0), len 100, sending
IP: s=172.12.123.1 (Serial0), d=172.12.123.3 (Serial0), len 56, rcvd 3
IP: s=172.12.123.2 (Serial0), d=172.12.123.3 (Serial0), len 100, rcvd

When there’s no entry in the routing table exists for a particular destination IP address, the packets aren’t leaving the router, the “debug ip packet” will result in the output like the following:

IP: s=172.12.123.3 (local), d=2.2.2.2, len 100, unroutable
IP: s=172.12.123.3 (local), d=2.2.2.2, len 100, unroutable
IP: s=172.12.123.3 (local), d=2.2.2.2, len 100, unroutable
IP: s=172.12.123.3 (local), d=2.2.2.2, len 100, unroutable
IP: s=172.12.123.3 (local), d=2.2.2.2, len 100, unroutable

 

The word unroutable indicates that no entry in the routing table exists for address 2.2.2.2 in this case.

The extended ping command,

Router#ping
allows extended ping where you have more control.
Pressing Control + Shift +6 twice stops the pings.

ICND1 and ICND2 break down

Advertisements

Make a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

2 Responses to “ICND1 break down — Pings and extended pings”

RSS Feed for IT Certifications Comments RSS Feed

[…] (CDP) * L1 and L2 Troubleshooting * Telnet and SSH Maintenance Commands * Administrative Distance * Extended Ping […]


Where's The Comment Form?

Liked it here?
Why not try sites on the blogroll...

%d bloggers like this: