While 70 percent of college students play video games at least “once in a while,” according to the Pew Research Center, some games are impossible to play on the University’s Wi-Fi.

Undeclared freshman Tiago Grimaldi Rossi said when he tried to play certain games online, such as “Call of Duty: Black Ops 4” and “Destiny 2,” a pop-up on his computer said “your NAT types are not compatible.” 

Network Address Translation, or NAT, is one problem students face when playing games on campus. At UT, there are only a certain amount of internet addresses shared among the student population. NAT allows for one IP address to be used for an entire private network.

Where your house may have one internet address shared by family and friends, the University has many addresses shared by thousands, according to William Green, director of networking and telecommunications for ITS. 

“Any large place has to use Network Address Translation to share those (internet addresses) among everybody,” Green said. “At any given instant during the day, we see about 70,000 devices connecting on (our network), and over a semester, we see 200,000 devices connecting.”

When creating a game, developers often use either client-to-client or client-to-server models. Games developed with the client-to-client model, which requires gamers to connect directly to other gamers, do not work on campus, said Jason Wang, senior information technology manager for ITS. When a gamer outside UT tries to reach students connected to the Wi-Fi, the NAT system remaps that student’s real address. 

“Most home routers have DMZ and/or port-mapping configuration options that allow you to manually create that mapping,” Wang said. “The DMZ and port-mapping configuration options are not something we are able to offer at scale on something the size of the University’s Wi-Fi.”

Students also reported having issues playing Nintendo Switch games, which run under this client-to-client model.

“The issue that we are seeing with some of these titles is they’re expecting to be able to establish direct client-to-client connections,” Wang said. “That’s where traversing that NAT perimeter becomes difficult.”

Students should have no issue playing games with client-to-server models, such as “Fortnite” and “World of Warcraft.” In client-to-server games, gamers connect to a server that is usually run by the game publisher or a game console company.

“Everyone’s able to establish connections to a common server, and the server communicates conversations back to all the connected players,” Wang said.