Firewall rule question

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Firewall rule question

1,364
267
NAS
DS 718+, 2x-DS 720+
Router
  1. RT2600ac
Operating system
  1. Windows
Mobile operating system
  1. iOS
Last edited:
Regarding RT2600ac firewall:
Say the rule I want to make involves allowing (or denying) IP of 192.168.1.100, and Wan IP of 8.8.8.8 (for this discussion).

My question is: do I need to make 1 or 2 rules to cover both inbound and outbound directions?
One 192.168.1.100 to 8.8.8.8 to cover outbound

And one 8.8.8.8 to 192.168.1.100 to cover inbound

I’m not clear on this… to cover both directions, 1 or 2 rules?

Thank you
 
Firewall rules work on connections (sessions). The initial packet will determine the source IP and destination IP, after this the rule is applied to packets in both directions. You have to create the firewall rule for those source and destination IPs.

If the reverse connection initiation is to be handled then you'll have to create a second rule. So to answer your question: to stop outbound connections from the LAN device will be one rule (LAN IP as source) and to stop inbound connections to the LAN device is a second rule (LAN IP as destination). In the latter situation you could just not have a port forwarding (NAT) rule instead. Inbound to private IPs are blocked by default due to no NAT.

If this was a packet filter router then you'd have to create two rules per firewall rule anyway, as packet filters don't link packets into sessions.
 

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