How does my computer work with an empty arp table?

[Lowell Gilbert]

a at zeos.net writes:

> My computer is connected to ISP via ADSL and works properly.
>
> I typed
>
> arp -a
>
> and saw an empty table, although I pinged successfully an Internet host
> one second ago.
>
> How does it work?
>
> ------------------------------------------------------------
>
> $ ifconfig
> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> 	options=8<VLAN_MTU>
> 	inet6 fe80::202:44ff:fe92:1875%rl0 prefixlen 64 scopeid 0x1 
> 	inet 192.168.1.2 netmask 0xffffff00 broadcast 192.168.1.255
> 	ether 00:02:44:92:18:75
> 	media: Ethernet autoselect (100baseTX <full-duplex>)
> 	status: active
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
> 	inet6 ::1 prefixlen 128 
> 	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 
> 	inet 127.0.0.1 netmask 0xff000000 
> ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1492
> 	inet6 fe80::202:44ff:fe92:1875%ng0 prefixlen 64 scopeid 0x3 
> 	inet 91.124.65.146 --> 195.5.5.161 netmask 0xffffffff 

Maybe you are connected to your service provider by PPP-over-Ethernet?
In that case, the PPP link (which doesn't need ARP) is your next-hop
to the Internet, rather than the modem on the Ethernet link.