How to Disable Stateful Firewall - How-to-Disable-Stateful-Firewall/How-to-Disable-Stateful-Firewall

• Disable the default firewall rule to drop packets not related to a valid firewall state
• Remove the netfilter policy responsible for dropping packets with an invalid state (example below)

filter [FORWARD]
-m state --state INVALID -j DROP 

• Cradlepoint Router

1. Log in to the Command Line Interface of your router NCOS: Command Line Interface (CLI) - Getting Started
2. Run this command: set config/firewall/drop_invalid_ipv4 false
3. To verify the current status of the setting, use this command: get config/firewall/drop_invalid_ipv4

• The default behavior of Cradlepoint routers is to act as a stateful firewall, and drop packets that are not related to an established connection or an existing ALLOW rule. For security reasons, this should be left on in most situations, but some specialized configurations may require this to be disabled.
• Detail of the firewall rule set can be seen with the "netfilter" CLI command. This rule usually looks like the following:  "-m state  --state INVALID -j DROP"