SMTP (25,587)

Ports

Port 25 📬:

• Used mainly for server-to-server email delivery

• Often blocked by ISPs to prevent spam

Port 587 🔒:

• Used by users to send emails through their mail provider

• Requires authentication (username & password)

• The modern, secure way to submit outgoing mail

Telnet

$ telnet 192.168.192.189 110
Trying 192.168.192.189...
Connected to 192.168.192.189.
Escape character is '^]'.
+OK POP3
USER [e-mail]
+OK Send your password
PASS Castello1!
+OK Mailbox locked and ready
LIST
+OK 0 messages (0 octets)
RETR 1
QUIT

Communication

swaks --to [e-mail] --from [e-mail] --header "Subject: Hello" --body @body.txt --attach @config.Lib-ms --server 192.168.1.1 --port 25 --auth LOGIN --auth-user [e-mail] --auth-password 'Pass123!'