How to Open pop3 and smtp ports in iptables firewall

Iptable-AINPUT-ptcp-dIP -- dport25-jACCEPTiptable-AINPUT-ptcp-dIP -- dport110-jACCEPT1, how do I close all ports? IPTABLES-AINPUT-DPROT1-65535-JDROP2 in the specified port that needs to be opened? (For example: 22) IPTABLES-AINPUT

Iptable-a input-p TCP/IP -- dport 25-j ACCEPT
Iptable-a input-p TCP/IP -- dport 110-j ACCEPT

1. how do I close all ports?
IPTABLES-a input-d prot 1-65535-J DROP

2. when specifying the port to be opened? (For example, 22)
IPTABLES-a input-d prot! 22-J DROP

3. What is the difference between prot and FORWARD?
PROT is the port. FORWARD. Is the data packet type.

Disable SMTP or POP3 ports

What new do users add in outlook, such as giga and yahoo ?, Directly inIptablesWhat are the ip addresses of the specified isp? Enter your 「? You can do that.
Iptables-a input-p tcp-I eth0-s (giga ip) -- sport (25 or 110)-d (your eth0 IP)-j DROP
OR
Iptables-a forward-p tcp-I eth1-s (client user ip)-d (giga ip) -- dport (25 or 110)-j DROP