How to permanently block udp on all ports on all connections including pppoe
55767
How can I make a specific set of iptables rules permanent?
139461
Permanently blocking a domain in iptables
58923
Allow Ubuntu Server Access only from specific IP's
93802
How to open port for a specific IP address with firewall-cmd on CentOS?
66612
How can I block ping requests with IPTables?
107326
How to ignore a set of Mac addresses in dhcpd.conf?
30972
How to disable IPv6 permanently?
68563
How do I restrict a specified SSH user to connect only from one IP or hostname?
26916
How do I with ufw deny all outgoing ports excepting the ones I need?
119187
How can I block the traffic outside the VPN, even if the VPN is down?
30755
ISP blocking port 25
136927
How to ensure OpenVPN connection uses specific DNS?
26826
Can't save firewalld rules with --permanent
89228
Exempt programs or domain from VPN connection
151957
Postfix: disable authentication through port 25
72612
Bind to ports less than 1024 without root access
155465
Can't access select https sites on Linux over PPPoE