[SOLVED] Mageia PCs don't reply to pings

[Parckwart]

I have two PCs with Mageia 4 installed. Both don't reply to pinging. Actually I can't connect to them in any way because I can't SSH them aswell. However my router detects them...

[doktor5000]

Check if ICMP (echo request - ping) is enabled in the firewall, the same for ssh - https://doc.mageia.org/mcc/4/en/content ... ewall.html

[jiml8]

Also, of course, make sure ssh daemon is running.

[wobo]

I confirm not receiving pings nor sending pings with my laptop, not even with my gateway (router).
Pinging my router with my desktop works ok.

Both machines are MGA4, laptop is a new installation, desktop is an upgrade from MGA3. Which points to a change in settings (I never touched these settings before).

[Parckwart]

Enabling in firewall settings worked.

[wobo]

Not here
Checking firewall settings was the first I tried before I wrote my forum post.

[nero]

Not here
Checking firewall settings was the first I tried before I wrote my forum post.

run that in a console and post result , so we can see your fw setup:

sudo iptables -L -n

[wobo]

I disabled firewall in total

Code: Select all

[root@marvin-1 wobo]# iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

[nero]

uhmm so if it's not a fw problem there should be some problem in the network , the source and the destination of the ping are in the same segment ?

[wobo]

All 3 devices (desktop, laptop, router) are in the same net segment - the usual home net.

[ITA84]

This is only for ping responding, but do you have any custom net configuration options in /etc/sysctl.conf or /etc/sysctl.d/?

[wobo]

No, as long as it works I tend to leave all of those untouched.

[ghmitch]

Aside from firewall:

If /proc/sys/net/ipv4/icmp_echo_ignore_all is set to "1", that will inhibit pings.

If /etc/sysctl.conf contains "net.ipv4.icmp_echo_ignore_all = 1", that will inhibit pings.

And it looks like SELinux can also interfere with pings.

[wobo]

If /etc/sysctl.conf contains "net.ipv4.icmp_echo_ignore_all = 1", that will inhibit pings.

Thanks, this was the culprit.
Leaves the question of who and when and why this was set to "1" - it used to be "0" until MGA3 (as I said, I never ever touched this kind of settings).

[doktor5000]

Hmmm, draknetcenter says that this settings is defined by the chosen security policy (msec)
https://doc.mageia.org/mcc/4/en/content ... ml#d4e1165

But either this is buggy, or something else is involved. I've ticked that box to disable ICMP, then quit, and then rerun draknetcenter, unticked the box and quit. No change in /etc/sysctl.conf and also the settings there do not reflect the settings from draknetcenter.

On further testing, draknetcenter writes it's settings to /etc/sysctl.d/51-drakx.conf
And by default /etc/sysctl.conf is ignored in Mageia 3 and 4: https://bugs.mageia.org/show_bug.cgi?id=12066

[wobo]

And by default /etc/sysctl.conf is ignored in Mageia 3 and 4: https://bugs.mageia.org/show_bug.cgi?id=12066

Hmm, after I changed that setting (from "1" to "0") the machine does serve ping replies, this does not look "ignored".

Or something totally different happened at the same time ....