ICMP ping response

English Network/Internet
1

Hi Guys,

How do I enable ICMP response for LEAP15.1?

Seem like by default it is disabled / blocked.

Thanks.

2

I have firewalld disabled, no iptables installed.

3

It is working fine here. It does not seem to be blocked.


% ping nwr8
PING nwr8.attlocal.net (192.168.1.70) 56(84) bytes of data.
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=1 ttl=64 time=0.251 ms
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=2 ttl=64 time=0.243 ms
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=3 ttl=64 time=0.265 ms
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=4 ttl=64 time=0.268 ms
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=5 ttl=64 time=0.286 ms
64 bytes from nwr8.attlocal.net (192.168.1.70): icmp_seq=6 ttl=64 time=0.257 ms
^C
4

Ping response can be controlled by setting ‘net.ipv4.icmp_echo_ignore_all’ using sysctl. For example to enable do…

echo "0" >  /proc/sys/net/ipv4/icmp_echo_ignore_all

and it can be made persistent by configuring in /etc/sysctl.conf, (or a config file in /etc/sysctl.d)

net.ipv4.icmp_echo_ignore_all = 0

FWIW, a similar thread where a user wanted to do the opposite
https://forums.opensuse.org/showthread.php/533866-How-to-block-incoming-ping

5

Ops, sorry, I mean incoming ping.

My Leap15.1 machine has IP 192.168.1.14.

I try to ping 192.168.1.14 from other machine and it is no response.

Below is another example

1039×714 49.9 KB

6

That’s what I thought I was testing.

My Leap15.1 machine has IP 192.168.1.14.

In the output that I showed, 192.168.1.70 is running Leap 15.1. I was pinging it from 192.168.1.66 (currently at Leap 15.0). And, as you can see, the Leap 15.1 machine responded.

7

that is so weird.

btw i was testing with virtualbox. i will try with real machine then.

8

That may explain the difference. I was testing with real machines.

9

Ok. I have tested with real machine too, and it works.

For unknown reason, with virtualbox it is not working.

And the other weird thing, with two virtualbox machine, each can response to each other.

Thank you.

10

That probably has to do with how networking is virtualized.

I use KVM for virtualization, and I use bridged network connections. So it will probably be different.

In any case, I am in the middle of switching my main desktop to Leap 15.1, and I have not yet installed the KVM virtualization.

11

Check that you’re using a bridged network connection. I usually have my guests appear as if they are on the same LAN.

12

yes, confirmed is bridged network connection.

13

Can’t remember previous version of LEAP has this issue.

I’m in the mid of switching all my office desktop and server to Leap15.1.

So I need to test OpenLDAP server/client, NFS, Autofs, Samba, Bind etc …