When you doing ping follow by arp, is that on the same machine or router ?
(each machine have it own arp cache)
If you do arp from the router, do the ping from there too.
after your reply I pinged from router to esp and then saw the mac address and IP address both. So that must have been the problem. Thank you.
Now I see my ESP in my Router active wireless client list. I am attaching the snapshot. as you can see it doesn't have any name associated with it. How can it be set??.
Also this client list is very temporary.It is disappearing very quickly and never comes back unless its pinged it from the router. any idea what can be the problem.
On Windows, I think there is a registry that can be created to change the default.
On your DLink DIR-600, I think this is hard-coded, but I'm not sure.
For the hostname issue, I'm not sure either, because I've tested changing it in my ESP using wifi_station_set_hostname() from the SDK (I don't know if Lua expose that) and it didn't change output of arp on my Linux machine, since arp rely on DNS entries. Maybe a workaround for you would be to use static DCHP IP on your router, in this case, you will provide the name in the router ifself.