1. What is POP3 and which are the default POP3 ports
Post Office Protocol version 3 (POP3) is a standard mail protocol used to receive emails from a remote server to a local email client. POP3 allows you to download email messages on your local computer and read them even when you are offline. Note, that when you use POP3 to connect to your email account, messages are downloaded locally and removed from the servers. This means that if you access your account from multiple locations, that may not be the best option for you. On the other hand, if you use POP3, your messages are stored on your local computer, which reduces the space your email account uses on your web server.
By default, the POP3 protocol works on two ports: Port 110 - this is the default POP3 non-encrypted port Port 995 - this is the port you need to use if you want to connect using POP3 securely