Re: [webmin-l] Strange issues with ICMP monitoring

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

So this is still happening with 1.979. I'm now bumping to 1.980, but not 
expecting much to change.

I've switched from Webmin's internal "ping" to using "Use command 
suitable for Linux or FreeBSD". No change.

I've moved the "ping monitors" to another host. No change.

Is there a way to enable some sort of debugging for "System and server 
status" pings ... ?

I run a self-written Python script on the same server, that basically 
does the same type of ping monitoring, and it *never* reports a "down" 
when Webmin does.

I'm confused :-)


-joho



On 2020-12-08 23:12, Joaquim Homrighausen wrote:
>
> Hi there
>
> As stated in the post(s), Webmin 1.962 on Ubuntu 20.04.LTS.
>
> We do indeed use fail2ban on the servers being "pinged", but the ping 
> interval is set rather high.
>
> The checking server all of a sudden starts reporting monitors as being 
> down, but they are actually not. If I ssh into that checking server, 
> and issue ping to the servers reported as being down by Webmin, I get 
> a response. Every time.
>
> If I reboot the checking server, which takes about 10-15 seconds, 
> everything goes back to normal.
>
> It sounds/looks to me like a "build-up" issue, but I've only ever seen 
> this on that particular server. It happened with Ubuntu 18.04.LTS, and 
> it's happening with Ubuntu 20.04.1.LTS.
>
> It happens frequently, but not every day.
>
> The checking server is not logging in to the remote servers, it's 
> simply sending ICMP/pings.
>
>
> -joho
>
>
> On 2020-12-08 23:04, Eric Tykwinski wrote:
>> Sorry new to the list, but what are you running?
>> VirtualMin, Webmin, Cloudmin?
>>
>> My first guess would be a fail2ban issue as that is a popular 
>> dictionary attack mitigation method, so a cluster of webmin servers 
>> with an incorrect password on one would cause this.