ARP ping instead of ICMP ping for gateway latency check ?

ARP ping instead of ICMP ping for gateway latency check ?

[Robin Roevens]

Hi All

I recently changed my internet provider and I noticed that both the
gateway graph on cgi-bin/netother.cgi and my Zabbix gateway ping check
no longer work.
It seems that my current provider blocks ICMP pings on the gateway
address.
So I was wondering if it wouldn't be better to use arping instead of
normal ping to check the latency of the gateway? This should always
works regardless of firewalls of the provider.. I think?

I can quite easily change this Zabbix check. But I'm not sure about the
graph on netother.cgi; I can look into that if you all think that
change would be a good idea? Or if anyone could give me some pointers
on where to start looking?

Regards
Robin

-- 
Dit bericht is gescanned op virussen en andere gevaarlijke
inhoud door MailScanner en lijkt schoon te zijn.

Re: ARP ping instead of ICMP ping for gateway latency check ?

[Michael Tremer]

Hello Robin,

> On 20 Apr 2025, at 23:52, Robin Roevens <robin.roevens@disroot.org> wrote:
> 
> Hi All
> 
> I recently changed my internet provider and I noticed that both the
> gateway graph on cgi-bin/netother.cgi and my Zabbix gateway ping check
> no longer work.

Yes, some ISPs don’t respond do ICMP echo requests to the gateway. I have no idea why really, but it is not uncommon.

> It seems that my current provider blocks ICMP pings on the gateway
> address.
> So I was wondering if it wouldn't be better to use arping instead of
> normal ping to check the latency of the gateway? This should always
> works regardless of firewalls of the provider.. I think?

This is a good idea. An ARP ping should always work, because otherwise there is no way to discover the layer 2 address of the gateway. But that obviously only applies to internet connections that actually use ARP. PPP connections don’t use ARP for example.

We are also using collectd which is using liboping and that only supports ICMP.

> I can quite easily change this Zabbix check. But I'm not sure about the
> graph on netother.cgi; I can look into that if you all think that
> change would be a good idea? Or if anyone could give me some pointers
> on where to start looking?

I think so. It could be an option for the future.

If the gateway does not respond to pings, you should automatically fall back to ping.ipfire.org <http://ping.ipfire.org/> though. So the graph should always have some data to show.

Best,
-Michael

> 
> Regards
> Robin
> 
> -- 
> Dit bericht is gescanned op virussen en andere gevaarlijke
> inhoud door MailScanner en lijkt schoon te zijn.
> 
> 

Re: ARP ping instead of ICMP ping for gateway latency check ?

[fairmont]

[-- Attachment #1: Type: text/plain, Size: 2095 bytes --]

Have you tried tracepath since it uses UDP?

tracepath -4 -b <outside ipV4 address>
or
tracepath -6 -b <outside ipV6 address>
or even
tracepath -b www.google.com

TCP ping would be another method.


On Tue, Apr 22, 2025 at 8:35 AM Michael Tremer <michael.tremer@ipfire.org>
wrote:

> Hello Robin,
>
> > On 20 Apr 2025, at 23:52, Robin Roevens <robin.roevens@disroot.org>
> wrote:
> >
> > Hi All
> >
> > I recently changed my internet provider and I noticed that both the
> > gateway graph on cgi-bin/netother.cgi and my Zabbix gateway ping check
> > no longer work.
>
> Yes, some ISPs don’t respond do ICMP echo requests to the gateway. I have
> no idea why really, but it is not uncommon.
>
> > It seems that my current provider blocks ICMP pings on the gateway
> > address.
> > So I was wondering if it wouldn't be better to use arping instead of
> > normal ping to check the latency of the gateway? This should always
> > works regardless of firewalls of the provider.. I think?
>
> This is a good idea. An ARP ping should always work, because otherwise
> there is no way to discover the layer 2 address of the gateway. But that
> obviously only applies to internet connections that actually use ARP. PPP
> connections don’t use ARP for example.
>
> We are also using collectd which is using liboping and that only supports
> ICMP.
>
> > I can quite easily change this Zabbix check. But I'm not sure about the
> > graph on netother.cgi; I can look into that if you all think that
> > change would be a good idea? Or if anyone could give me some pointers
> > on where to start looking?
>
> I think so. It could be an option for the future.
>
> If the gateway does not respond to pings, you should automatically fall
> back to ping.ipfire.org <http://ping.ipfire.org/> though. So the graph
> should always have some data to show.
>
> Best,
> -Michael
>
> >
> > Regards
> > Robin
> >
> > --
> > Dit bericht is gescanned op virussen en andere gevaarlijke
> > inhoud door MailScanner en lijkt schoon te zijn.
> >
> >
>
>
>

[-- Attachment #2: Type: text/html, Size: 2920 bytes --]