I have a 3825 with 1 nme-xd-48es-2s-p and 1 hwic 4esw. My ISP provides two public static IP's. I want to come from the cable modem to a 3-port DMZ (on the 4ESW), pass one IP to my firewall and the other to a second firewall. Basically, use the 4ESW as a dumb switch only. Both firewalls are set up as static IP's and the public IP's are in the same /28 subnet so I don't see a need for layer 3 here.
When I connect all 3 to a new vlan only one of the firewalls pass traffic. If I pull the 3 cables and put into a simple Netgear 5 port switch all traffic flows. I suspect this is an arp issue somewhere, but I cant figure out for sure.
I've tried setting the DMZ vlan to no ip, a bogus ip, nothing helps. My hunch is the Cox modem is taking the first 2 MAC's it sees and binding them to the two IP's, and one of those MACs is the vlan MAC maybe?
It does the same thing when I try to do this in the NME-XD too.
