Why is AsusWRT Merlin dropping all my port forwards?

[s_Fanous]

Hi,

I've setup my port forwards and have been testing them but all ports appear to be closed from the internet. I've tried to see what's happening within the router using tcpdump and all forwarded ports exhibit the same symptom

18:55:22.845337 IP 88.198.46.51.54232 > <My_IP>.12345: Flags [S], seq 2562065767, win 7300, options [mss 1460,sackOK,TS val 3870539 ecr 0,nop,wscale 8], length 0
18:55:22.849238 IP <My_IP>.12345 > 88.198.46.51.54232: Flags [R.], seq 0, ack 2562065768, win 0, length 0
18:55:56.172784 IP 88.198.46.51.54244 > <My_IP>.60291: Flags [S], seq 2629128671, win 7300, options [mss 1460,sackOK,TS val 3873872 ecr 0,nop,wscale 8], length 0
18:55:56.175576 IP <My_IP>.60291 > 88.198.46.51.54244: Flags [R.], seq 0, ack 2629128672, win 0, length 0
18:56:26.138703 IP 88.198.46.51.54270 > <My_IP>.12345: Flags [S], seq 2764619006, win 7300, options [mss 1460,sackOK,TS val 3876869 ecr 0,nop,wscale 8], length 0
18:56:26.140183 IP <My_IP>.12345 > 88.198.46.51.54270: Flags [R.], seq 0, ack 2764619007, win 0, length 0

For some reason the router is immediately sending a reset packet to any port I've forwarded. Now if I don't forward the port the port is of course reported as closed but tcpdump shows a different outcome

19:09:33.487291 IP 88.198.46.51.59994 > <My_IP>.443: Flags [S], seq 3389742135, win 7300, options [mss 1460,sackOK,TS val 3955606 ecr 0,nop,wscale 8], length 0
19:09:34.479066 IP 88.198.46.51.59994 > <My_IP>.443: Flags [S], seq 3389742135, win 7300, options [mss 1460,sackOK,TS val 3955706 ecr 0,nop,wscale 8], length 0
19:09:36.479054 IP 88.198.46.51.59994 > <My_IP>.443: Flags [S], seq 3389742135, win 7300, options [mss 1460,sackOK,TS val 3955906 ecr 0,nop,wscale 8], length 0

I've tried to disable the firewall on the router to see if it was the culprit but that has not changed the outcome.

Anyone having similar issues or know what the cause could be?

TIA

 

[s_Fanous]

Turned out to be a client firewall issue!!! Doh!!!