Log into your router and turn on UPnP (Universal Plug and Play), most routers have this option in the Administration tab.

The goal is to have an OPEN NAT in order to host Spec Ops games and get a wider selection of MP matches to join.

Also ensure that under your security options that Anonymous NAT Redirection is allowed and is not filtered. This may also be referred to as 'Filter InternetNAT Redirection' - in which case you want this disabled.

For more information on enabling UPnP on your router, visit your router manufacturer's website. A few of the most popular router web sites are listed below:

    * Linksys: http://www.linksysbycisco.com/support
    * Netgear: http://kb.netgear.com/app/
    * D-Link: http://www.dlink.com/support/
    * Belkin: http://en-us-support.belkin.com/