Which of the following default port numbers need to be open on a firewall for a mail server to successfully send and receive mail? (Choose three.)

Port 22 is used by SSH (Secure Shell) for encrypted remote administration sessions and plays no role in mail server send or receive operations.

Port 25 is the default port for SMTP (Simple Mail Transfer Protocol), used for server-to-server mail relay and delivery, which is required for the server to send outbound mail.

Port 53 is used by DNS (Domain Name System) for hostname resolution - while mail routing depends on DNS indirectly, DNS is not a mail protocol and this port does not need to be open on the mail server itself.

Port 80 is used by HTTP for unencrypted web traffic and is not associated with any standard mail server send or receive protocol.

Port 110 is the default port for POP3 (Post Office Protocol version 3), which allows mail clients to connect to the server and download messages to their local device.

Port 143 is the default port for IMAP (Internet Message Access Protocol), which allows mail clients to access, read, and manage messages stored directly on the mail server.

Port 161 is used by SNMP (Simple Network Management Protocol) for monitoring and managing network devices and has no involvement in mail delivery or retrieval.