Client connections always use an ephemeral port?

Question

When a client connects to something on the internet, does it always connect from an ephemeral port? Are all the well-known ports only used by servers?

Answer 1

Ports below 1024 are reserved only for use by root / the administrator. This is a standard security feature which stops a normal user masquerading as a system service / daemon. The majority of well-known services run on ports < 1024.

As a result all user connections have to come from a port > 1024.

Unless it is a specific requirement of the software (such as a some UDP peer-to-peer scenarios) it really doesn't matter what port number the connection originates from as the remote end is told about the connection's origins as soon as the connection request arrives.

So in summary: Usually and If it's below 1024.