Henceforth, "Door" refers to "New Door," not the old machine that is broken. It is latest Debian.
Door has three network cards: eth0 going to cable modem, eth1 going to fixed IP LAN segment, eth2 going to DHCP LAN segment. Door is running both DNS and DHCP servers.
Door can see everything in the world, on all cards. Complete functionality.
DHCP side can see everything in the world, on all cards. Complete functionality.
Fixed IP machines can all see Door (including its DNS services), and each other, and talk to the DHCP side, but can talk to nothing living out on eth0.
tcpdump on Door shows Door handing off ICMP packets on eth0, so that direction seems okay.
I am not seeing ACKs coming back to Door on eth0 from google.com but I can't be sure they aren't doing something tricky and my filters are confused.
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 126.96.36.199 0.0.0.0 UG 0 0 0 eth0 188.8.131.52 0.0.0.0 255.255.255.248 U 0 0 0 eth1 184.108.40.206 0.0.0.0 255.255.255.255 UH 0 0 0 eth1 220.127.116.11 0.0.0.0 255.255.255.255 UH 0 0 0 eth1 18.104.22.168 0.0.0.0 255.255.255.255 UH 0 0 0 eth1 22.214.171.124 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
Door is 126.96.36.199 (on eth0), 188.8.131.52 (on eth1), 192.168.1.1 (on eth2). 184.108.40.206 is the modem. 220.127.116.11 is a network to eth1.
Anybody know wtf?
eta: The router - in addition to not showing door any ACKs for anything from .42 and .43 - is sending out a lot of ARP packets looking for 18.104.22.168 and 22.214.171.124, and I'm starting to think it won't talk to a gateway box in the fixed-IP range. I try to add .41 as a gateway address for .42 and .43 and it refuses, saying illegal LAN address. SUPER RAGIFICATION ENGAGED.
eta2: And the new problem is that the PS4 won't pick up the gateway information from the Linux-based DHCP server. It will pick up an address! It's also not getting the DNS server number either. Why? Fuck if I know, everything else does it right.