Private VLAN on Arista EOS Switch (How ISP isolates traffic between subscribers)
The other day, I was looking at the arp table entry for my home router and found a funny thing going on - $ show arp Address HWtype HWaddress Iface 10.10.10.1 ether 04-96-AF-EF-C6-53 eth0 10.10.10.10 ether 04-96-AF-EF-C6-53 eth0 Above arp table is an example hiding the actual IP addresses and MAC addresses. Here my IP address is let's say - 10.10.10.50/24 and GW is 10.10.10.1 . Now the question comes why another subscriber of the ISP in the same subnet (10.10.10.10) also have same mac address as my GW (04-96-AF-EF-C6-53). We are in the same IP network/VLAN (ISP definitely configured those), but my router cannot see the actual MAC address of other devices in the network. The reason is that my ISP is isolating devices in layer-2 using a technique called private vlan. All of my layer-2 and layer-3 traffic within my subnet is proxied through the ISP router. We the different subscribers cannot see each other