Any one can explain ip ping question

Hi Expert
Can you explain the ip ping question? Here is topology: two routers connect to each other with its interface e1/0. The Router1 can ping R2'loopback 0, which is 2.2.2.2 255.255.255.252. The R2 has only two interface, e1/0 and loopback0. The R1 can ping 2.2.2.2. but why can the R1 also ping 2.2.2.3 ? After i changed R2' loopback0 ip address into 2.2.2.2 255.255.255.255, The R1 cannot ping 2.2.2.3 again. Here is config

R1

interface Ethernet1/0
 ip address 1.1.12.1 255.255.255.0

ip route 2.2.2.0 255.255.255.0 Ethernet1/0

R2
interface Loopback0
 ip address 2.2.2.2 255.255.255.252
interface Ethernet1/0
 ip address 1.1.12.2 255.255.255.0

ip route 0.0.0.0 0.0.0.0 Ethernet1/0
EESkyAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

N-WCommented:
Assigning Loopback0 the address 2.2.2.2 255.255.255.252 means that interface is a part of the 2.2.2.0/30 network.

The valid host addresses for that network are "2.2.2.1" and "2.2.2.2", but "2.2.2.3" is designated as the broadcast address for that network. Being a loopback interface, it will respond R1 or any other router when they attempt to ping the broadcast address.
0
Don JohnstonInstructorCommented:
You're saying that R1 can ping 2.2.2.3 even though that IP address is not assigned to a host???

Can you post the output of the ping showing that?
0
EESkyAuthor Commented:
@donjohnston, yes, i did not assign 2.2.2.3 to R2 or any interface. The ping showing is same as normal.
0
Determine the Perfect Price for Your IT Services

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden with our free interactive tool and use it to determine the right price for your IT services. Download your free eBook now!

Don JohnstonInstructorCommented:
Well, if you're describing the topology accurately, then the results you're getting are... impossible.

If you could post the configs of both routers and the session output when you're doing the pings, that would help.

BTW, is this being done of real routers or simulators?
0
EESkyAuthor Commented:
Yes, i think you are right. i use gns3, and i doubt the output. i'm gonna repeat doing it and then post it back. Thank you.
0
Don JohnstonInstructorCommented:
Ahh, I see.

GNS will give very accurate results, but there's always a chance of... weirdness.
0
N-WCommented:
Both GNS3 and Cisco's Packet Tracer will allow you to ping the broadcast address. In the real world, you will not be able to.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
EESkyAuthor Commented:
pinging broadcast and host has different output. in gns3 pinging broadcast is like ping host ip address, see below

R1#ping 2.2.2.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 44/61/84 ms

R1#ping 255.255.255.255

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 255.255.255.255, timeout is 2 seconds:

Reply to request 0 from 1.1.12.2, 68 ms
Reply to request 1 from 1.1.12.2, 84 ms
Reply to request 2 from 1.1.12.2, 24 ms
Reply to request 3 from 1.1.12.2, 72 ms
Reply to request 4 from 1.1.12.2, 48 ms
0
N-WCommented:
"255.255.255.255" is the broadcast address for the "0.0.0.0" network, which in Internet Protocol standards stands for this network, i.e. the local network.

For your purposes, it is the same as pinging "2.2.2.3" which is the broadcast for the "2.2.2.0/30" network.

You are able to ping the broadcast using both methods, but depending on which router operating system you're running, the output of both commands may look different.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Routers

From novice to tech pro — start learning today.