Since this is my first post I'll introduce myself before asking for everybody's help
I recently purchased a Routerboard 433 for my home because we kept burning out cheap consumer routers. I have 5 roommates plus myself (college...) in my house, so in total there are 6 computers, 4 XBox 360s, 2 PlayStation 3 consoles, and a wifi VOIP phone (T-Mobile UMA). The entire house is networked over 100mbps Ethernet and wireless. I believe everyone is using the wired connection except the phone and a laptop. As you can imagine, with 10+ hosts and multiple QOS rules for voice traffic, etc, I needed more than 16MB of RAM. All this then feeds into the Routerboard which is NATed over a 6mbps (800k up) ADSL connection with a single public IP.
Now I am fairly qualified when it comes to networking. I am a junior electrical engineering student and work for my university networking and telecom. department, but we have so many public IPs (its ridiculous, we throw them around like candy...I want a few) that my experience with NAT is fairly limited. I also mainly use Cisco IOS, so I love that RouterOS is setup a lot like IOS is. My problem is with XBox Live. Its a real pain and very picky about NAT implementations. Since there are 4 of Xbox hosts, individual port forwarding is not an option. I also do not have access to my roommates consoles or systems, so all settings must be configured from the router.
So far I have setup a simple src-nat with masquerade, and enabled UPNP. Each machine gets a static DHCP lease. This results in what the Xbox calls a "Moderate" NAT type - I want an "Open" NAT type (strict is the worst I guess). Unfortunately there seems to be very little technical information available about what Xbox live actually wants. All Microsoft can do is recommend an "Xbox live certified router" or tell me to forward UDP port 3074. Neither of these is an option. The odd part is - the DD-WRT box with UPNP worked fine with multiple consoles, as does a $25 Netgear wireless router with UPNP on. But again, none of these tell me what is actually going on! They are so simple I can't seem to replicate their settings.
Does anybody have any suggestions? If a crappy Netgear or DD-WRT can do it, RouterOS must be able to. I have tried 3.17 and 4.0Beta1. It seems to be more than just turning on UPNP, unless the RouterOS implementation of UPNP isn't working correctly with the XBox. If anyone has solved this issue (or a similar issue with NAT and identical private host applications) please let me know! And thanks for the great forum!