NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
cable modem uses it's public IP on LAN
My C7000 cable modem sometimes uses it's public IP and MAC address on the LAN.
Internet: 98.xxx.xxx.95, a0:04:60:x:xx:c9
LAN: 172.16.0.1, 255.255.255.255, a0:04:60:xx:xx:ca
11:54:29.355222 In a0:04:60:xx:xx:ca > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 172.16.0.17 tell 172.16.0.1
11:54:30.778173 In a0:04:60:xx:xx:c9 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 172.16.0.2 tell 98.xxx.xxx.95
11:54:35.819975 In a0:04:60:xx:xx:c9 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 172.16.0.2 tell 98.xxx.xxx.95
11:54:40.796601 In a0:04:60:xx:xx:c9 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 172.16.0.2 tell 98.xxx.xxx.95
The first line shows it correctly using it's LAN IP (172.16.0.1) and MAC (a0:04:60:xx:xx:ca) when ARPing for a LAN device.
The other lines show it incorrectly using it's public IP (98.xxx.xxx.95) and MAC (a0:04:60:xx:xx:c9) when ARPing for 172.16.0.2.
C7000
Xfinity
Hardware 1.05
Firmware V1.01.33
3 Replies
Thats just the logs reporting NAT operations.
The public IP is not being used on the LAN side of the fence.
Sorry, I should have specified the logs I posted were from an Ethernet device on my local network. The logs were not from the Netgear.
So I see frames with the Netgear cable modem WAN IP and MAC appearing on my LAN wires. Maybe Xfinity messed something up.
I factory reset the modem, but am still seeing the frames. If only I could SSH into the Netgear I might be able to figure something out. My devices are ignoring the ARPs since the requester is not on their subnet.
11:50:36.593959 In a0:04:60:xx.:xx:c9 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 192.168.0.200 tell 98.xxx.xxx.95
You can contact the ISP and NG support to see if there is any information regarding this. Again, this maybe the handling of NAT operations...
