Broadcast ping on linux

why doesn’t broadcast ping work?

When I try to ping bradcast 10.254.239.255 from Freebsd itself nothing happens:

--- 10.254.239.255 ping statistics --- 3 packets transmitted, 0 packets received, 100.0% packet loss 

• #arp -a says:
  .
  ? (10.254.239.255) at (incomplete) on sk0 expired [ethernet]
  .
• Firewall allows all on this interface

Where to look? What to do to make broadcast working?

3 Answers 3

If you want to perform host discovery, don’t use broadcast pings, just simply ping each possible permutation for a given subnet. It sounds heavy, but it actually takes seconds (brackets are important):

$ time ( s=192.168.0 ; for i in $(seq 1 254) ; do ( ping -n -c 1 -w 1 $s.$i 1>/dev/null 2>&1 && printf "%-16s %s\n" $s.$i responded ) & done ; wait ; echo ) 192.168.0.5 responded 192.168.0.11 responded 192.168.0.2 responded 192.168.0.254 responded 192.168.0.4 responded real 0m1.317s user 0m0.004s sys 0m0.084s 

While it does offer an alternative way to ping the network, it doesn’t answer the questions posed as to «why doesn’t broadcast ping work?»

True, but call it pragmatic intuition. I suspected there was an underlying reason as to why this person was trying to broadcast ping the network. I don’t see any harm in going beyond the answer to provide a possible solution. 😉

Most operating systems simply ignore broadcast ICMP pings by default, for security reasons. You don’t «make it work», and it has no effect on other kinds of broadcasts.

On FreeBSD, the net.inet.icmp.bmcastecho sysctl toggles this feature.

I know this question is very old, but it’s one of the top result when googling ‘ubuntu broadcast ping’.

I would like to add that you can send broadcast ping requests (ICMP echo-requests) very easily from a Linux host, with the option -b. Microsoft, for some reason, doesn’t allow this.

Here’s a broadcast ping sent from an Ubuntu host:

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 192.168.1.247: icmp_seq=1 ttl=64 time=0.031 ms 64 bytes from 192.168.1.254: icmp_seq=1 ttl=64 time=0.960 ms (DUP!) 64 bytes from 192.168.1.202: icmp_seq=1 ttl=64 time=92.3 ms (DUP!) 

Note the -b option to allow broadcast. As you can see, several hosts on my network have replied, including a Cisco switch, my own Ubuntu host, and an Apple laptop.

And yes, as others have said before, broadcast pings are terrible for scanning a network. Some hosts simply ignore echo-requests. There are much better tools for this purpose (E.g. nmap).

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Top 10 Ping Command Examples in Linux

In this tutorial, I will take you through Best Ping Command in Linux. Ping is a computer network administration software utility used to test the reachability of a host on an Internet Protocol network. It is abbreviated as «Packet Internet Groper». It is available for virtually all operating systems that have networking capability, including most embedded network administration software.

Often we think How to ping ip address or how to ping google or how to use ping ttl in Linux. To Know how to ping ip address, you need to first understand how ping command works. To understand how to ping ip address in a simple way you can just ping on google ip and check. Once you understand this you will also understand how to ping google, ping ttl values and how to ping on a specific address. I have covered sections like how to ping ip address, how to ping google, ping on ip address, ping ttl values below. Initially we all start by ping on google ip and understand how to ping google.

Ping Command in Linux

It sends ICMP ECHO_REQUEST to network hosts. It is a tool to check and verify if the destination node is up or not. It also gives few more information like RTT(round trip time), no of packets transmitted, no of packets received etc. We will look at the few best ping command examples below.

How to Ping IP Address

To understand how to ping ip address, you need to understand the Ping Command Syntax as mentioned below:-

How to Ping Internet

If you want to check if internet is working in your system or not, you can ping on Google DNS Address and check.

[root@localhost ~]# ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=49 time=46.4 ms 64 bytes from 8.8.8.8: icmp_seq=2 ttl=49 time=50.5 ms 64 bytes from 8.8.8.8: icmp_seq=3 ttl=49 time=46.2 ms 64 bytes from 8.8.8.8: icmp_seq=4 ttl=49 time=50.6 ms

How to Ping Google Address

If you want to ping on google, you need to use ping google.com command. This is the very basic command anyone can use to understand how to ping google address in Linux using ping command.

[root@localhost ~]# ping google.com PING google.com (216.58.197.78) 56(84) bytes of data. 64 bytes from maa03s21-in-f78.1e100.net (216.58.197.78): icmp_seq=1 ttl=48 time=41.6 ms 64 bytes from maa03s21-in-f78.1e100.net (216.58.197.78): icmp_seq=2 ttl=48 time=41.9 ms 64 bytes from maa03s21-in-f78.1e100.net (216.58.197.78): icmp_seq=3 ttl=48 time=42.2 ms

What is Ping TTL

Ping TTL means time to live. In above section of How to ping google address, you might have seen ping ttl value of 48. It means packets will only live for 48 network hops and then it will be discarded. ping ttl is an important parameter to trace the packets.

To ping on local interface using continuous ping Command

If you want to check if the localhost is up and running, you can perform continuous ping command in Linux and check.

[root@localhost ~]# ping localhost PING localhost (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.034 ms 64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.041 ms 64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.040 ms 64 bytes from localhost (127.0.0.1): icmp_seq=4 ttl=64 time=0.047 ms 64 bytes from localhost (127.0.0.1): icmp_seq=5 ttl=64 time=0.051 ms 64 bytes from localhost (127.0.0.1): icmp_seq=6 ttl=64 time=0.037 ms

If you want to check the local interface is up or not through IP address instead of hostname, you can run below continuous ping command in Linux and check:-

[root@localhost ~]# ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.044 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.078 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.058 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.050 ms 64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.066 ms

To set interval of 2 seconds between each packets

If you want to send total of 5 packets with a time interval of 2 seconds between them, you can do that by continuous ping command using -i ping options. The default value is one second.

[root@localhost ~]# ping -i 2 -c 5 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. 64 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.335 ms 64 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.275 ms 64 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.350 ms 64 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.273 ms 64 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=0.277 ms

To enable pinging a broadcast

If you want to ping a broadcast address, you need to use -b switch with ping command in Linux.

[root@localhost ~]# ping -b 192.168.0.255 WARNING: pinging broadcast address PING 192.168.0.255 (192.168.0.255) 56(84) bytes of data. ^C --- 192.168.0.255 ping statistics --- 53 packets transmitted, 0 received, 100% packet loss, time 52182ms

To limit the number of Network hops

If you want to set the TTL(time to live) value of packets, you can use -t switch with ping command.

[root@localhost ~]# ping -t 10 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. 64 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.298 ms 64 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.245 ms 64 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.307 ms 64 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.280 ms 64 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=0.298 ms

Change the default packet size from 56 to 100.

To change the default packet size from 56 bytes, you need to use -s ping options along with the specified packet value.

[root@localhost ~]# ping -s 100 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 100(128) bytes of data. 108 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.315 ms 108 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.338 ms 108 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.269 ms 108 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.260 ms 108 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=1.16 ms

Ping Options to enable verbose output

If you want to enable the verbose feature of ping request, you need to use -v ping options with below ping command in Linux.

[root@localhost ~]# ping -v 192.168.0.104 ping: socket: Permission denied, attempting raw socket. PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. 64 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.302 ms 64 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.306 ms 64 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.316 ms 64 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.378 ms 64 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=0.282 ms 64 bytes from 192.168.0.104: icmp_seq=6 ttl=64 time=0.245 ms

To enable debugging of IP Packet

If you want to enable debugging feature of IP Packet, you need to use -d continuous ping options.

[root@localhost ~]# ping -d 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. 64 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.355 ms 64 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.314 ms 64 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.326 ms 64 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.257 ms 64 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=0.865 ms 64 bytes from 192.168.0.104: icmp_seq=6 ttl=64 time=0.286 ms

Set time to wait for a response from ping server

If you want set time to wait for a response in seconds, you can use -W ping options. This option affects only timeout in absence of any responses, otherwise ping waits for two RTTs.

[root@localhost ~]# ping -W 10 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. 64 bytes from 192.168.0.104: icmp_seq=1 ttl=64 time=0.295 ms 64 bytes from 192.168.0.104: icmp_seq=2 ttl=64 time=0.336 ms 64 bytes from 192.168.0.104: icmp_seq=3 ttl=64 time=0.271 ms 64 bytes from 192.168.0.104: icmp_seq=4 ttl=64 time=0.329 ms 64 bytes from 192.168.0.104: icmp_seq=5 ttl=64 time=0.264 ms

To specify preload value

If preload is specified,continuous ping command sends that many packets without waiting for any reply. Only the super-user may select preload more than 3.

[root@localhost ~]# ping -l 5 192.168.0.110 PING 192.168.0.110 (192.168.0.110) 56(84) bytes of data. From 192.168.0.105 icmp_seq=1 Destination Host Unreachable From 192.168.0.105 icmp_seq=2 Destination Host Unreachable From 192.168.0.105 icmp_seq=3 Destination Host Unreachable From 192.168.0.105 icmp_seq=4 Destination Host Unreachable From 192.168.0.105 icmp_seq=5 Destination Host Unreachable From 192.168.0.105 icmp_seq=6 Destination Host Unreachable From 192.168.0.105 icmp_seq=7 Destination Host Unreachable From 192.168.0.105 icmp_seq=8 Destination Host Unreachable ^C --- 192.168.0.110 ping statistics --- 8 packets transmitted, 0 received, +8 errors, 100% packet loss, time 3000ms pipe 8

To send more than 50,000 packets in few seconds.

If you want to flood any server in your network with packets, you can use continuous ping command with -f switch to ping server.

[root@localhost ~]# ping -f 192.168.0.104 PING 192.168.0.104 (192.168.0.104) 56(84) bytes of data. .^ --- 192.168.0.104 ping statistics --- 51024 packets transmitted, 51024 received, 0% packet loss, time 26936ms rtt min/avg/max/mdev = 0.059/0.419/47.685/1.311 ms, pipe 2, ipg/ewma 0.527/1.663 ms

Reference: Ping Documentation

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