[webmin-l] Strange issues with ICMP monitoring

[Joaquim H. <jo...@we...>]

Hello, hope everyone is safe from the stuff that's going on.


I seem to have come across a really strange issue with ICMP monitoring 
or "Ping".

On a host running Webmin 1.960 and Ubuntu 18.04.LTS, I get error reports 
from *all* monitors of the type "Ping", indicating the monitor is down.

It only happens on this particular host.

What's strange is that other monitors, like HTTP/WEB (80/443) monitors 
all work, even those to the same hosts. Doing a check with mtr -r -c 10 
<host> from the Webmin host to any of the failing monitored hosts, 
everything looks good.

If I do a "manual" ping, using "ping <host>", everything looks good.

Re-starting Webmin does not help. Doing a "shutdown -r now" on the 
Webmin host works.

Time to wait for response is set to 10s.

I've tried using both hostnames and IP-addresses, no difference. All 
hostnames resolve to IPv4 addresses only.

I would really like to nail this odd behavior ... is there any way I can 
configure some more debug output from Webmin monitors?

There are no weird entries in /var/webmin/webmin.log

The only "error looking" entries in /var/webmin/miniserv.error I can see 
are these, but they don't appear to be related to this issue:


[06/Nov/2020:00:30:50 +0200] IPv6 support cannot be enabled without the 
Socket6 perl module
[06/Nov/2020:00:30:50 +0200] Using MD5 module Digest::MD5
[06/Nov/2020:00:30:50 +0200] Using SHA512 module Crypt::SHA
[06/Nov/2020:00:30:50 +0200] PAM authentication enabled
Use of uninitialized value in numeric ne (!=) at 
/usr/share/webmin/bind8/bind8-lib.pl line 2406.
[08/Nov/2020:20:55:12 +0200] miniserv.pl started
[08/Nov/2020:20:55:12 +0200] IPv6 support cannot be enabled without the 
Socket6 perl module
[08/Nov/2020:20:55:12 +0200] Using MD5 module Digest::MD5
[08/Nov/2020:20:55:12 +0200] Using SHA512 module Crypt::SHA
[08/Nov/2020:20:55:12 +0200] PAM authentication enabled
Use of uninitialized value in numeric ne (!=) at 
/usr/share/webmin/bind8/bind8-lib.pl line 2406.
[10/Nov/2020:21:22:06 +0200] miniserv.pl started
[10/Nov/2020:21:22:06 +0200] IPv6 support cannot be enabled without the 
Socket6 perl module
[10/Nov/2020:21:22:06 +0200] Using MD5 module Digest::MD5
[10/Nov/2020:21:22:06 +0200] Using SHA512 module Crypt::SHA
[10/Nov/2020:21:22:06 +0200] PAM authentication enabled



-joho