Is mu to mu a security risk?

[gbs]

I work on a campus, with 500+ students.

Actually we dont have any kind of auth to the wifi, everyone can access it.

But there is too many complaints about whatsapp calling not working.

And we checked that this problem happens when we disable mu to mu communication.

When mu to mu communication is activated, does it allow someone to sniff packets? Can i let this mu to mu communication activated without any security problem?

[gbs]

If i use wpa2 / aes with a password that every student know, this can protect them against sniff? Or at least be a little more secure?

[Timo1]

WPA2 is more secure than open network. But each student who know the PSK can encrypt traffic from all other. Additional they can create "honeypots" and to "man in the middle" stuff.
A secure solution is WPA2 (AES only) with authentication. TLS perfect, PEAP-MSCHAPv2 works with properly configured devices (must check and verify the AAA server).

[gbs]

So it will be more secure in which way?

[Christopher_Fra]

Absolutely and definitely will be more secure, but the students with the passphrase could definitely sniff/packet capture, due to having the passphrase.