{"id":46,"date":"2024-02-17T21:30:31","date_gmt":"2024-02-17T21:30:31","guid":{"rendered":"https:\/\/pfsensesetup.com\/opnsenseinstall.com\/?p=46"},"modified":"2024-02-17T21:30:51","modified_gmt":"2024-02-17T21:30:51","slug":"creating-firewall-rules-in-opnsense","status":"publish","type":"post","link":"https:\/\/pfsensesetup.com\/opnsenseinstall.com\/creating-firewall-rules-in-opnsense\/","title":{"rendered":"Creating Firewall Rules in OPNsense"},"content":{"rendered":"\n

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OPNsense is essentially software that works as both a router and a firewall. It is a router because it can route traffic from one network to another; it is a firewall because it can block traffic from one network to another. A firewall is implemented with packet filters, gateways, demilitarized zones, encryption and logging. Network Address Translation (NAT) may be part of a firewall, but it will be discussed in a separate article.<\/p>\n\n\n\n

A firewall may not just be a packet filter; it may incorporate higher levels of security: systems for detecting and preventing intrusions for packets that should not be there due to security rules. A firewall may incorporate a honeypot, or a honeynet, which rebuilds a regular network with fake hosts which allows the security team to study attack patterns.<\/p>\n\n\n\n

For purposes of this article, we will consider firewall rules. OPNsense is a stateful firewall, which means that it is connection-oriented. The reply packets of a connection do not require a separate rule \u2013 they are automatically allowed.<\/p>\n\n\n\n

The first match rule makes the order of the rules important. Rules are evaluated from the top down; if the packet matches the rule, this rule is evaluated and the rest are ignored. A blocking rule at the beginning of the ruleset makes the rest of the rules ineffective.<\/p>\n\n\n\n

The rules should be sorted by this plan:<\/p>\n\n\n\n