These high-numbered ports are probably dynamic ports or
Ephemeral ports.
If you are indeed referring to these above ports,
they are temporary ports used by the processes that make up Chrome and its tabs.
These ports are allocated by Windows with random numbers, that are not under
the control of Chrome. As it's not possible to predict the port numbers,
it's also not possible to block them.
In any case, blocking these ports will render Chrome unusable.
The dynamic port range on Windows can be viewed by using the following commands:
netsh int ipv4 show dynamicport tcp
netsh int ipv4 show dynamicport udp
netsh int ipv6 show dynamicport tcp
netsh int ipv6 show dynamicport udp
The new TCP and UDP default start port is 49152, and the default end port is 65535.
This port range can be modified by using the following command:
netsh int <ipv4|ipv6> set dynamic <tcp|udp> start=number num=range
Example:
netsh int ipv4 set dynamicport tcp start=10000 num=1000
netsh int ipv4 set dynamicport udp start=10000 num=1000
These examples set your dynamic port range to start at port 10000 and to end at port 11000 (1000 ports).
A few important things to know about the port range:
- The smallest range of ports that can be set is 255.
- The lowest starting port that can be set is 1025.
- The highest end port (based on the range set) cannot exceed 65535.