How to ping from loopback interface of router

[mirror512]

I have seen the lab for CCNP ROUTE exam it stataes that you must aable to ping and telnet from loopback interface 101 on R1 to ip address like 172.1.1.1

Now is that ping different from normal ping. because ping command is same i think

[darren.g]

>"Router#ping 172.16.1.1 source lo0

>                      ^

That's indicating the "ping" command is not recognised at all, not the arguments. Are you sure the ^ is appearing after the "ping"? What happens if you type

ping?

[shiramat]

Hey Darren,

First of all i'm trying to ping from a loopback interface to an IP address of the router interface.

Yes as per the previous post of you, i executed the command "ping 172.16.1.1 source loopback 10" as you see from the above image.

-> When i execute this, i get:

R3#ping 172.16.1.1 source loopback 10

                   ^

% Invalid input detected at '^' marker.

-> If i type ping? i get:

R3#ping ?

  WORD  Ping destination address or hostname

  ip    IP echo

-> If i execute ping normally like this:

R3#ping 172.16.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 2/3/6 ms

it goes fine, which is the ping from one interface to another

So is there a different method of how we execute ping command from a loopback interface?

Please advise.

regards,

Sagar

[smitesh kharecha]

Hi Sagar,

Not sure about the packet tracer, but following are the options which you can use on router / switch.

Option 1: ping x.x.x.x source lo0

Option 2:

PING IP

Target IP address: x.x.x.x

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]:

[paul driver]

Hello Sagar,

It sounds like the IOS ( software) of the router is a old version which doesn't include this way of specifying source.

Try using the extended ping.

Ping  (press  enter)

Protocol [ip]:( press enter)

Target IP address (enter target address)

Repeat count [5]:( press  enter)

Datagram size [100]:( press  enter)

Timeout in seconds [2]:( press  enter)
Extended commands [n]: Y

Source address or interface: loopback10  ( press  enter)

Type of service [0]: ( press  enter)

Set DF bit in IP header? [no]:( press  enter)

Validate reply data? [no]:( press  enter)

Data pattern [0xABCD]:( press  enter)

Loose, Strict, Record, Timestamp, Verbose[none]:( press  enter)

Sweep range of sizes [n]:( press  enter)

res

Paul

Being able to

Please don't forget to rate this post if it has been helpful.

[shiramat]

Hi Paul,

thanks for the reply.

I'm trying to ping from loopback 10 to 172.16.1.1.

so target IP address would be 172.16.1.1

when i enter Y in extended commands, i'm able to enter only 172.16.1.2 as Source address / interface. It is not taking the loopback10 command neither its takes the 10.10.10.3.

Also how we will know from which loopback address are we pinging if it doesn't allow loopback ip address but allows to enter 172.16.1.2, which is the main interface?

Seeing that it allows only main interface ip address, it seems that it is how the s/w is designed by default, if you can make me understand on this, that would be awesome!!

thanks,

Sagar

[shiramat]

Hi Paul,

it worked, i could get it done. Its just that i had configured loopback 10 on a wrong interface.

regards,

Sagar

[paulstone80]

Hi Sagar,

I think this may be a limitation within Packet Tracer. You don't get the full IOS within the PT devices, and a lot of commands and extended command features are missing.

What output do you get if you type: ping 172.161.1.1 ?

HTH

Paul



****Please rate useful posts****

[shiramat]

Hi Paul,

if i type: ping 172.16.1.1, its get successful

R3#ping 172.16.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 2/3/6 ms

thanks,

Sagar

[Sam Den]

I have version packet tracer version 7.2.1 i am failing from the loopback interface on a router. This is what i get,

r1#ping

Protocol [ip]: 192.168.30.3

% Unknown protocol - "192.168.30.3", type "ping ?" for help

[shiramat]

Thanks a lot guys for all the suggestions. Will be back in case of any more queries. You guys have been of great help

[paul driver]

Hello Sagar,

Please don't forget to rate these posts if they have been helpful.

res

Paul

[#13]

OK -  I know that this is over six years OLD and I know that it is probably answered 100 times elsewhere. But I am still answering the question.

type ping - press enter

fill out the form & at the Extended commands choose/type Y and enter the source address

Extended commands [n]: y

Source address or interface: 5.5.5.5

Router#ping

Protocol [ip]:

Target IP address: 6.6.6.6

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 5.5.5.5

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 6.6.6.6, timeout is 2 seconds:

Packet sent with a source address of 5.5.5.5

.....

Success rate is 0 percent (0/5)

-----------OR - with success --------------

Router#ping

Protocol [ip]:

Target IP address: 5.5.5.5

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 6.6.6.6

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 5.5.5.5, timeout is 2 seconds:

Packet sent with a source address of 6.6.6.6

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/0 ms

Also - as a note - when using RIP, you will need to advertise both 5.5.5.0 and 192.168.1.0. Otherwise the the 5.5.5.0 or 6.6.6.0 networks will never make it across to the correct router.

[AmineBensabeur]

there is two ways to do so easy way is (let's suppose R1 is your router)
R1#ping 172.1.1.1 source (ip address of the loopback ) 
or 
R1 # ping 

Protocol [ip]:

Target IP address: 172.1.1.1

.

.

Source : (ip address of the loopback ) 

.

[americain35]

Thanks very much guys for this post.  I have had the same issue with pinging from a loopback port.  Big up!!!