Guides tagged “firewall”
Step-by-step MdmHost guides about firewall, sorted A-Z.
76 guides · page 4 of 4
Restrict outgoing traffic with UFW egress rules
Switch UFW to deny outgoing traffic by default, then allow only DNS, NTP, HTTPS and package mirrors. Block outbound SMTP and avoid breaking system updates along the way.
Secure Remote Desktop on Windows Server
Stop password-guessing on Remote Desktop with strong passwords, Network Level Authentication, a lockout policy and firewall rules limited to your IP.
Set up a UFW firewall on Ubuntu and Debian
Set safe defaults, allow SSH before switching UFW on, open only the ports you use, limit sensitive ports to your own IP, and tidy up old rules.
Stop Docker from bypassing your UFW firewall
Docker-published ports skip UFW rules and stay open to the internet. Learn why it happens, how to bind ports to 127.0.0.1, how to filter with the DOCKER-USER chain and how to test from outside.
Switch from CSF to the Imunify360 firewall (root guide)
Move a cPanel server from CSF/LFD to the Imunify360 firewall as root: plan the switch, migrate allow and deny lists, open the right ports and verify nothing is locked out.
TCP vs UDP explained for server owners
TCP sets up a connection and guarantees delivery; UDP sends independent datagrams with no handshake. Learn the difference, which services use each and why firewall rules must name the protocol.
Test firewall changes safely with an automatic rollback
Schedule an automatic undo before you change firewall rules. If a mistake blocks SSH, the old rules come back by themselves a few minutes later.
Tune LFD login failure blocking and email alerts in CSF
Adjust LFD triggers, block durations, permanent blocks and alert emails so CSF stops brute-force attacks without flooding your inbox or blocking genuine users.
UFW and IPv6: make sure your rules cover both
Check that UFW filters IPv6 as well as IPv4. Set IPV6=yes, read the (v6) rules in ufw status, allow or deny IPv6 sources and test your server from outside with nmap -6.
UFW vs firewalld vs nftables vs iptables: which Linux firewall to use
UFW, firewalld, nftables and iptables are not four rival firewalls. Learn how they fit together, what each distro uses by default and how to pick one tool for your VPS.
Use Fail2ban with firewalld or nftables ban actions
Make Fail2ban put its bans into the firewall your server really uses. Set banaction to firewalld rich rules or nftables, check the distribution defaults and confirm bans in the live ruleset.
What is a firewall? Network, host and web application firewalls explained
Learn what a firewall does, how network, host-based and web application firewalls (WAF) differ, and which ones protect a cPanel server, VPS or website.
Which firewall ports a cPanel/WHM hosting server needs
A complete list of the ports cPanel, WHM, webmail, email, FTP, SSH and DNS use, which ones to open in your firewall, and which you can safely close.
Why is my IP blocked? How to find out and get unblocked
Recognise the signs of a firewall block on cPanel hosting, find your public IP, learn the usual causes such as wrong mail passwords, and get unblocked quickly.
Windows Firewall: Preventing Unauthorized Incoming Connections on Server Roles
Review the inbound rules that Windows server roles add, then replace broad allow rules with scoped ones so only the hosts that need a service can reach it.
Write firewalld rich rules for IP-based access
Use firewalld rich rules to open a port to one IP, rate-limit new connections, and log or reject traffic. Covers runtime vs permanent rules and how to list and remove them.
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