How does my computer work with an empty arp table?

[a at zeos.net]

On Mon, Dec 04, 2006 at 10:26:46AM -0500, Lowell Gilbert wrote:
> 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.

Yes, you are right, I forgot about PPP. Many thanks.