VPS Firewall

A firewall is an essential security component that filters network traffic on your server.

Overview

What is a Firewall

A firewall monitors incoming and outgoing network traffic based on defined rules. It allows you to:

• Allow or block specific ports
• Filter traffic by IP address
• Restrict access to services

Accessing the Firewall

You can manage the firewall in two ways:

1. Via CoreSynth Panel

In your dashboard, go to your VPS server and select the Firewall section.

2. Via Terminal (UFW)

sudo ufw status
sudo ufw allow 80/tcp
sudo ufw deny 22/tcp

Adding Rules

Rule Parameters

Rule Examples

# Allow HTTP
sudo ufw allow 80/tcp
 
# Allow HTTPS
sudo ufw allow 443/tcp
 
# Allow SSH from specific IP
sudo ufw allow from 192.168.1.100 to any port 22
 
# Block specific IP
sudo ufw deny from 10.0.0.50
 
# Allow port range
sudo ufw allow 1000:2000/tcp

Recommended Rules

Basic Server Protection

# SSH only from your IP (CHANGE IP!)
sudo ufw allow from YOUR_IP to any port 22
 
# HTTP and HTTPS
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
 
# Default policy - block everything else
sudo ufw default deny incoming

Note: Replace YOUR_IP with your actual IP address.

Managing Rules

View Active Rules

sudo ufw status numbered

Delete a Rule

sudo ufw delete allow 80/tcp

Edit a Rule

Rules cannot be directly edited. First delete the old rule, then add a new one:

sudo ufw delete allow 22/tcp
sudo ufw allow 2222/tcp

Firewall Monitoring

Statistics

sudo ufw status verbose

Firewall Logs

# View recent entries
sudo tail -f /var/log/ufw.log
 
# Enable logging
sudo ufw logging on

Troubleshooting

Cannot Connect via SSH

Cause: Firewall rule blocking SSH port.

Solution:

# View current rules
sudo ufw status
 
# Allow SSH
sudo ufw allow 22/tcp

Website Not Working

Cause: Firewall blocking HTTP/HTTPS ports.

Solution:

sudo ufw allow 80/tcp
sudo ufw allow 443/tcp

Firewall Blocking Everything

Cause: Too restrictive rules.

Solution:

# Temporarily disable firewall
sudo ufw disable
 
# Reset all rules
sudo ufw reset

Enabling and Disabling Firewall

# Disable firewall
sudo ufw disable
 
# Enable firewall
sudo ufw enable
 
# Reset all rules
sudo ufw reset

Next Steps

• VPS Security — Advanced server security
• Backups — Back up your data

Need help? Open a support ticket  or ask Alex.