Forwarding TCP packets from RED to ORANGE

From my post

another doubt arises for me.
I created a new topic because I think the topic is no longer about CU174.
Move as you see fit, though.

The question is this:
Why are some packets (TCP) coming from IPFire’s RED IP (192.168.111.4) not being forwarded to 172.16.3.1 (ORANGE)?
176.n.n.n is the external IP, which “bombards” port 68nn (TCP) on my router. My router does port forwarding to 192.168.111.4:68nn (IP RED IPFire) and IPFire should turn all TCP traffic to 172.16.3.1:68nn
But it seems that some TCP packets are not being forwarded, am I right? Why?
Thank you in advance.

Or do those LOGs refer to packets not coming from 176.n.n.n is, but directly from 192.168.111.4?
If so I think I understand.
But no. The source is 176.nnn from what I see.

The top one is the source and the bottom one the destination for the IP’s in the logs.

Your rules have defined a source port of 68nn and a destination port of 68nn but the traffic that was dropped had a source port of 49267 and a destination port of 68nn. Therefore that traffic did not match with the rule that was looking for a source port of 68nn and the traffic was dropped. You need additional rules for the different source ports that might be used in addition to 68nn or if it should always be coming from 68nn then the rule did its job and dropped the traffic coming from a different port.

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Yes. I think that’s what happened!
I thank you for the valuable clarification.
I learn more and more things :wink:.

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