if you are like me and have a cisco pix, firewall then you may have noticed from your xbox, telling you your NAT settings are less than ideal(mine was Moderate). to save you all the work here is the NAT config to get your pix firewall working.
note: the game works without this config, but will have issues with chat, searching, etc.
also, my xbox was telling me "NAT: Moderate" when i would do a diagnostic test.
sample setup:
cisco pix 501 firewall - ip address 192.168.0.254 (inside interface), dhcp address from cable provider (outside interface)
xbox 360 - ip address 192.168.0.100
pix config (must already be configured for basic NAT)
--create access list for xbox live packets
access-list xboxlive_inbound permit tcp any interface outside eq 3074
access-list xboxlive_inbound permit udp any interface outside eq 3074
access-list xboxlive_inbound permit udp any interface outside eq 88
--define static nat translations, where 192.168.0.100 is your xbox ip address
static (inside,outside) tcp interface 3074 192.168.0.100 3074 netmask 255.255.255.255 0 0
static (inside,outside) udp interface 3074 192.168.0.100 3074 netmask 255.255.255.255 0 0
static (inside,outside) udp interface 88 192.168.0.100 88 netmask 255.255.255.255 0 0
--apply access list to allow inbound traffic on outside interface matching above rules
access-group xboxlive_inbound in interface outside
now, re-run your xbox diagnostics, and boot up. The game and your box will now report that your NAT settings are Open.
later.
