I notice in our organisation an access list which is allowing tcp and udp ports greater than 1.
Why are ports (TCP and UDP) 0 and 1 used for. As I was reading on the internet i noticed that tcp port 1 is used for service multiplexing.
So when 2 hosts are trying to connect to eachother via port 80 www. It will first setup a tcp connection via syn and ack, after this the www service of host 1 is searching for www service of host 2 via port 1. when www is found there is a positive sign send to host 1 over tcp port 1. Is this correct?
When is port 0 used?
Again on the internet I found that these ports are a kind of a wildcard. When host 1 wants to send something over port 0 it is redirected to the next available port above 1023. And are those ports (above 1023) used for virusses and trojans?
Is this the way virus outbreaks are started?