Use of WSUS is to patch other servers. We need to create Group policy, make changes in the policy for Windows update and link it to a domain.When you install WSUS, it will take some hours for the servers to be listed in the WSUS console. So it is better to give a day for the servers to come up in the console
1.We can patch servers that are not in domain using WSUS to do that, we need to execute the below commands on servers that are not in domain. Open command prompt run as administrator and execute below:
wuauclt /resetauthorization /detectnow wuauclt /reportnow
2. WSUS default port is 8530
3. You can use WSUS client diagnostic tool to troubleshoot incase if a client is not listed in WSUS server.