Hi, I would like to know how many clients can be contacted to 1 deco m5?

I know 1 deco M5 can split 255 IP addresses (DHCP), but it is clear to me, that not all 255 products can be contacted to the Internet at the same time (over wifi).

I want to know, in practice what the number of the products that really can connect out to the internet, when connected in wifi to one deco unit M5 and at the same time.