differt types of pings

[pramod]

Hello,

I am trying to do some of these commands on router. what actually happens behind the background when i issue these ping commands. Responses appreciated.

-kgpramod

R1#ping 1.1..1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.1.0.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

R1#

R1#ping 1..1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.0.1.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

R1#

R1#

R1#

R1#sh ver

Cisco IOS Software, 7200 Software (C7200-ADVENTERPRISEK9-M), Version 12.4(15)T6, RELEASE SOFTWARE (fc2)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2008 by Cisco Systems, Inc.

Compiled Mon 07-Jul-08 16:46 by prod_rel_team

ROM: ROMMON Emulation Microcode

BOOTLDR: 7200 Software (C7200-ADVENTERPRISEK9-M), Version 12.4(15)T6, RELEASE SOFTWARE (fc2)

R1#ping 1.1.1..

% Unrecognized host or address, or protocol not running.

R1#

R1#

R1#

R1#ping ..1.1.1

% Unrecognized host or address, or protocol not running.

R1#ping 1..1..

% Unrecognized host or address, or protocol not running.

R1#ping 1.1..1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.1.0.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

R1#

R1#ping 1.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms

R1#

[mfurnival]

Not really sure what kind of answer you are looking for here but the different results you see are related to the syntax checking of the IOS command line. Without seeing the source code it is impossible to say precisely why it does what it does but it is obviously expects the IP address as a parameter to the ping command and it expects it in the usual format (4 integers between 0 and 255 separated by dots). If you get it wrong it tells you - it looks like if you just miss an integer out it fills in a zero for you.

[InayathUlla Sharieff · Accepted solution]

Pramod,

To be frank not sure what you are trying to achieve here. Its always recommended to use the valid ip address to ping.

Ref of how Ping works.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6057.shtml

To be frank I have not seen anyone doing this type of testing in my career of networking.

Anyways let me help you:

1-

R1#ping 1.1.1..

% Unrecognized host or address, or protocol not running.

Answer:>>>> this is correct as you are not supposed to lef dots as a lost octet hence it will show you as unrecognized ip address.

2-

R1#ping ..1.1.1

% Unrecognized host or address, or protocol not running.

Answer:>>> Again same answer as 1st question.

3-

R1#ping 1..1..

% Unrecognized host or address, or protocol not running.

Answer>> There is no way you can define this type of address as this doesnt exist.

4-

R1#ping 1.1..1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.1.0.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

Answer:>> This considers the ip address to be 1.1.0.1 but it doesnt have any entry as such hence packet gets dropped.

If you configure any of your loopback interface with the ip 1.1.0.1 you would get respose.

5-

R1#

R1#ping 1.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:

!!!!!

Answer:>>> This is valid hence you get the response. Please see the link which i posted how ping works.

Hope this clarified your doubt.

Regards

Inayath

*Please rate if this info is helpfull to you.

[pramod]

It's always better to have syntax showing : % Unrecognized host or address, or protocol not running. : for all the scenarios. I am curious to know whats happening behind the scenes! Thanks Sharieff