I was just wondering, whenever i do a ping, I usually get a timeout on the first ping then the next ping will be fine.
is this normal?
Im using Cisco 3560,3750,6500, and ASA5505.
Disabling arp (if you could) would make a difference - you would get no responses and the network would not work!
There is not a lot you can do about the loss of the first ping, as has been said, it is perfectly normal and is due to the delay involved in arping the target.
You really don't want to disable arp on any of your devices unless you want to statically map all the mac-addresses on each of your devices which is a huge job :)
if you entered a static entry in the arp table on the device you are pinging from for the destination device then you would avoid losing the first packet but to be honest i wouldn't bother.
Appreciate the rating, many thanks
The reason you often lose the first packet on a ping is because of arp. Without a mac-address the packet cannot be delivered to the destination machine. If the mac-address of the destination or the mac-address of the default-gateway is not present in the arp cache on the source machine it must first arp out for the the mac-address.
That is why you often lose the first packet. It doesn't happen so much with end clients usually because they only need the mac-address of their default-gateway and they are usually communicating on the network most of the time so the mac-address is always in the cache.
But for example if you go into one of your switches and ping the vlan interface of another one of your switches on the same subnet it is quite likely that you will see the first packet dropped. If you then ping again straight away all pings should get a response.