Frequently losing internet connection, ARP table looks weird

dave247 · Dec 22, 2014, 6:54 AM

I've been having a lot of weird connectivity issues with pfsense lately, exactly like the guy in this post: https://forum.pfsense.org/index.php?topic=60892.0.

One thing I just noticed in my ARP table (view the attached screenshot) is that there appears to be two entries with two addresses assigned to the same mac address which clearly shows part of the problem. There is no way this should have happened unless somehow ARP poisoning…

Let me explain my setup: The pfsense WAN nic is connected to my cable modem. The LAN nic is connected to a Cisco unmanaged switch. The dv6700 is just my laptop that is connected to the switch. Pfsense's DHCP issues it a 10.0.0.0/24 address. There is NO WAY that my laptop should have acquired that public address from my modem, so the ARP table is wrong. I have never connected this laptop to my modem and I have not changed any of my network's topology in weeks.

I'm losing my mind over this problem and have been looking all over pfsens's settings for a possible solution for days now.

EDIT: I am an idiot. I accidentally spoofed my WAN address with that of the internal host which I was accessing the webConfigurator with.
![ARP Table wtf.jpg](/public/imported_attachments/1/ARP Table wtf.jpg)
![ARP Table wtf.jpg_thumb](/public/imported_attachments/1/ARP Table wtf.jpg_thumb)

Supermule · Dec 22, 2014, 6:28 AM

You dont run any WIFI from that cable modem do you???

dave247 · Dec 22, 2014, 6:53 AM

Nevermind, I finally figured out what the problem is… and the simplest answer is the right one. There were two identical mac addresses. Why? Because I accidentally clicked on the "Insert my local mac address" on the LAN config page, thus spoofing my WAN mac with that of an internal host on my network.... hahahahahahaa.. live and learn I guess.