LARTC - Jun 2005 - Re: LARTC Digest, Vol 4, Issue 9

Daniel Lopes wrote:
> Ping a client you surely know should be connected to the switch. ARP
> will take the part to find out the hardware address so the packet can be
> delivered. If the switch is on it should find a hardware address and ARP
> should put it in your ARP cache. It´s independet from ICMP blocks and
> similar. So after trying to ping you should have an entry in your ARP
> table which you can control with "arp" command.
> 
> 
It seems that I didn''t make myself quite clear ...

I want to know if there is a way to find out if a switch is working ok or not.

If there is something like a small device, that I plug into the
switch, ant then if that device "reports in" ok, then I know the
switch is working.

Like on a router... if you want to know if a router is doing it''s job,
than you send an ICMP echo request to a host on the other side of the
router.
ME ----> ROUTER -----> testing host

well, I want the same thing but on an inferior layer, on a switch.
ME -----> SWITCH ----> testing device

I want to know if thare can be such thing as a "testing device".

I thought of an ethernet card, that i plug in the switch, power the
card up, and then somehot arping the card, from witch I know the MAC.
... but i don''t think it works  just like that :(.


Hope I was specific enough this time .... 

Thanks for the (possible) answers.

Best regards,
Radu.


-- 


Radu Cugut

mobile: +40 742 045686
web:    http://rcugut.has.it

Radu CUGUT schrieb:
> Daniel Lopes wrote:
> 
>>Ping a client you surely know should be connected to the switch. ARP
>>will take the part to find out the hardware address so the packet can be
>>delivered. If the switch is on it should find a hardware address and ARP
>>should put it in your ARP cache. It´s independet from ICMP blocks and
>>similar. So after trying to ping you should have an entry in your ARP
>>table which you can control with "arp" command.
>>
>>
> 
> 
> It seems that I didn''t make myself quite clear ...
> 
> I want to know if there is a way to find out if a switch is working ok or
not.
> 
It seems you can´t read. To ping someone you exactly know is connected 
to the switch is the easiest way to get an arp cache entry. If you don´t 
get an entry the switch is not working or the other one is blocking arp 
what shouldn´t happen because he wouldn´t be able to receive any 
packets. Just try what I said. Blocking protocols like ICMP doesn´t have 
an impact on the work of arp respectively ethernet. Exactly spoken no 
impact of getting the hardware address.