Hi Bulek,
By default the MQX examples using Ethernet (MQX4.0/demo/web_hvac or the MQX4.0/rtcs/examples/httpsrv) can have more than one client access them.
The default setting for the RTCSCFG_TCP_MAX_CONNECTIONS is 0 (which means there is no limit).
If you want to change this #define setting do it in the user_config.h header and recompile the RTOS components.
Obviously an infinite number of connections cannot occur. Just realize each connection used up a certain amount of RAM and sooner or later you will run out.
Regards,
David