Saw there are a few posts on the subject but nothing seemingly this specific.
When setting up my router a few weeks ago I found I had to unblock 10.36.96.1 on my WAN interface for DHCP client and server. Had to reboot the router last night to change out a card, and now I find a route from DHCP for 172.19.73.156, and that the DHCP server for the WAN interface is the same 172.19.73.156. The address I leased did not change. Text-chatted with and then called COX to try to find out if this was valid and they could not confirm other than that my DHCP-issued IP address was indeed the one their system showed, and they were unwilling to forward me to their network security team.
Anyone else seen DHCP servers from multiple different private ranges? I would like to write an ACL but there is no way I'm allowing private addresses into or out of my WAN interface without good cause. It already doesn't make sense to me that they would use RFC1918 addresses on their WAN, but it makes even less sense to use addresses in two vastly different blocks.
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