Dear folks,
I am not seeing this error right away. Trying to NAT and port forward with the following rule as attached.
WAN is 192.168.254.2/24 (NAT If)
LAN is 172.16.16.0/24 (Test If)
While the incoming request is seen, it seem like the outgoing reply is NATed separately with a wrong source port:
16:01:11.446958 IP 109.41.1.5.14631 > 192.168.254.2.8080: Flags [S], seq 568671719, win 14600, options [mss 1460,sackOK,TS val 460198899 ecr 0,nop,wscale 9], length 0
16:01:11.447756 IP 192.168.254.2.38922 > 109.41.1.5.14631: Flags [S.], seq 415419811, ack 568671720, win 14480, options [mss 1460,sackOK,TS val 190102564 ecr 460198899,nop,wscale 7], length 0
16:01:12.446936 IP 109.41.1.5.14631 > 192.168.254.2.8080: Flags [S], seq 568671719, win 14600, options [mss 1460,sackOK,TS val 460199899 ecr 0,nop,wscale 9], length 0
16:01:12.447656 IP 192.168.254.2.38922 > 109.41.1.5.14631: Flags [S.], seq 415419811, ack 568671720, win 14480, options [mss 1460,sackOK,TS val 190103563 ecr 460198899,nop,wscale 7], length 0
16:01:12.447755 IP 192.168.254.2.38922 > 109.41.1.5.14631: Flags [S.], seq 415419811, ack 568671720, win 14480, options [mss 1460,sackOK,TS val 190103564 ecr 460198899,nop,wscale 7], length 0
16:01:14.447865 IP 192.168.254.2.38922 > 109.41.1.5.14631: Flags [S.], seq 415419811, ack 568671720, win 14480, options [mss 1460,sackOK,TS val 190105564 ecr 460198899,nop,wscale 7], length 0
Hence, the connection never establishes.
Any idea how this could be misconfigured?
The problem was an overlapping outbound NAT.