What Services and thier port numbers should be allowed in (CSF)firewall?

[Dipak Bhoi]

Hello folks,

In this post I mentioned the necessary services and their port should be opened by default in firewall on the server. Here I am considering that you are using CSF (Config Server Firewall) as a firewall to secure your server.

Beneath is the list of services and their port numbers, open these ports in firewall.

TCP_IN = "20,21,22,25,53,80,110,143,443,465,587,993,995"

TCP_OUT = "20,21,22,25,53,80,110,113,443"

UDP_IN = "20,21,53"

UDP_OUT = "20,21,53,113,123"

Services using these open ports are:

    Port 20: FTP data transfer

    Port 21: FTP control

    Port 22: Secure shell (SSH)

    Port 25: Simple mail transfer protocol (SMTP)

    Port 53: Domain name system (DNS)

    Port 80: Hypertext transfer protocol (HTTP)

    Port 110: Post office protocol v3 (POP3)

    Port 113: Authentication service/identification protocol

    Port 123: Network time protocol (NTP)

    Port 143: Internet message access protocol (IMAP)

    Port 443: Hypertext transfer protocol over SSL/TLS (HTTPS)

    Port 465: URL Rendesvous Directory for SSM (Cisco)

    Port 587: E-mail message submission (SMTP)

    Port 993: Internet message access protocol over SSL (IMAPS)

    Port 995: Post office protocol 3 over TLS/SSL (POP3S)

Apache Server:

TCP_IN: 80,443

Mail server:

TCP_IN: 25,110,143,587,993,995
TCP_OUT: 25,110

MySQL server (if remote access is required)

TCP_IN: 3306
TCP_OUT: 3306

FTP server:

TCP_IN: 20,21
TCP_OUT: 20,21
UPD_IN: 20,21
UPD_OUT:20,21

Open necessary ports as per your requirements and enjoy the service .... !!!