Q. What is a port?
A port is software docking point in your machine where remote application uses for communication. This is analogy to the physical ports for entering in to the Countries.
Q. What is hardware port?
This is physical peripheral connection point to a machine from a physical device.
Q. What is a socket?
Socket is mix of software Port+IP address.
Q. What is the range of ports or how many ports are there?
Port numbers can vary from 0 to 65535, so total we can get 65536 ports
Q. Why port numbers are just 65536?
This is because limitation in TCP/IP stack where the port field is just 16bit size. So we get only 2^16 port which is equal to 65536 ports
Q.What are the well-known ports?
Well known ports are from 0 to 1023(total 2^10=1024 ports)
Q.What do you mean by default port?
Default port is a designated port for particular well-known server.
Q.Can we change default port for a service(example Apache, squid)?
Yes, we can change
Q.What are the protocol numbers for TCP and UDP?
TCP protocol number:6
UDP protocol number:17
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