POP3
used TCP port 110.
110
port 21 FTP port 25 E-mail SMTP port 80 web server HTTP port 110 E-mail POP3
21 port - FTP (File Transfer Protocol) 25 port - SMTP (Simple Mail Transfer Protocol) 110 port - POP3 (Post Office Protocol used by email clients) 80 port - HTTP (World wide web Portocol) Services: port 21- FTP, port 25- Secure shell, Port 80- Web Server and port 110-Web Server Protocol: port 21-FTP, port 25- SSH, port 80- HTTP and port 110- POP2
TCP port 110 is POP3 - Post Office Protocol 3 -It is used to retrieve email that was stored for the receipient
110
generally smtp is on 25 and pop3 is on 110. but there are different ports for different types of mail servers too.
Set the firewall rule to block/deny any packets to port 110. You could also not use your email client, which uses port 110. Programs themselves can be blocked on certain ports by more advanced firewalls.
110
Telnet operates over TCP Port 23.
TCP port 110 is POP3 - Post Office Protocol 3 - It is used to retrieve eMail that was stored for the receipient.
23 is for telnet,25 is for SMTP,20 is for FTP and 110 is for POP3