Pinging Broadcast Address – What You Need to Know

broadcasticmpnetwork-discoveryping

Iam using linux.I read somewhere in the internet that pinging the 255.255.255.255 will ping everyone in the network segment. And it will return every ip addresses in that subnet. but when i tried

ashokkrishna@ashokkrishna-Lenovo-B560:~$ ping -b 255.255.255.255
WARNING: pinging broadcast address
PING 255.255.255.255 (255.255.255.255) 56(84) bytes of data.
64 bytes from 192.168.1.220: icmp_seq=1 ttl=64 time=100 ms
64 bytes from 192.168.1.220: icmp_seq=1 ttl=64 time=100 ms (DUP!)
64 bytes from 192.168.1.220: icmp_seq=2 ttl=64 time=128 ms
64 bytes from 192.168.1.220: icmp_seq=2 ttl=64 time=130 ms (DUP!)

I am only getting the reply from only one ip. how to get every ip, I know how to get every ip with nmap but what I read in the internet is totally opposite in my senario why?

same with

ashokkrishna@ashokkrishna-Lenovo-B560:~$ ping -b 192.168.1.255
WARNING: pinging broadcast address
PING 192.168.1.255 (192.168.1.255) 56(84) bytes of data.
64 bytes from 192.168.1.220: icmp_seq=1 ttl=64 time=55.2 ms
64 bytes from 192.168.1.220: icmp_seq=1 ttl=64 time=66.6 ms (DUP!)
64 bytes from 192.168.1.220: icmp_seq=2 ttl=64 time=78.5 ms
64 bytes from 192.168.1.220: icmp_seq=2 ttl=64 time=79.2 ms (DUP!)

Best Answer

Not all machines will answer a broadcast ping. (all broadcast -- 255.255.255.255, or subnet broadcast -- eg. x.x.x.255) Some see it as a "security feature", because one could spoof the origin to flood any host on the network.

Related Solutions

How to trace outgoing interfaces

I's not exactly the answer at your question, but that a simple (but limited) way to do (in certain case) what you want. I'm coping-post the option -R of ping man page:

-R Record route. Includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note that the IP header is only large enough for nine such routes. Many hosts ignore or discard this option.

So you can see also the return path of the ECHO_REQUEST, that is not the exit interface (that you are asking about) unless the outgoing path is the same of the come back path. Only in this case, the returning path is the IP address of the outgoing interface you are asking for.

That's an real example on my internet provider net, maybe not so clear, but I don't have just now some router to link each other :) dest 10.2.105.178

traceroute 10.2.105.178
traceroute to 10.2.105.178 (10.2.105.178), 30 hops max, 60 byte packets
 1  192.168.1.254 (192.168.1.254)  3.418 ms  3.575 ms  4.021 ms
 2  10.189.48.1 (10.189.48.1)  11.237 ms * *
 3  10.2.105.178 (10.2.105.178)  15.235 ms * *

ping -R 10.2.105.178 PING 10.2.105.178 (10.2.105.178) 56(124) bytes of data.

64 bytes from 10.2.105.178: icmp_req=5 ttl=253 time=74.1 ms NOP RR:

192.168.1.133

10.189.51.61

10.2.105.177

10.2.105.178

10.2.105.178

10.189.48.1

192.168.1.254

192.168.1.133

----omitted----

64 bytes from 10.2.105.178: icmp_req=6 ttl=253 time=13.0 ms NOP RR:

192.168.1.133

10.189.51.61

10.2.105.177

10.2.105.178

10.2.105.218 ##change every time, Idon't know why##

10.189.48.1

192.168.1.254

192.168.1.133

Understanding Broadcast Address in Networking

I can obtain the broadcast address, by replacing all the n/w bits to 1)

Actually you set the host bits to 1, not the network bits.

Your other points are OK.

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