@PlusPlus 

The lack of response could also mean that a packet filter dropped the probe or any response it elicited.

Some ports need to be open for the network service, but when PortCheckTool tries to access those ports, the router doesn't reject nor accept, it just doesn't give any response, because the firewall is working. So we don't need to worry about the port security.

Not sure if it's the reason, what ports are not responding when you test it? Do you mean those ports is closed on your old Router? Have you already set a virtual server on R605?

@Virgo 

• Virtual Server ports are forwarded on TL-R605 exactly the same as on my old router.
• They are routed to various IP cameras on my property.
• I am unable to access cameras that use these TCP ports: 8086,8086, 10000,10001,18086, 18087, 53, 88, 20000, 30000, and so on.  I've tried more ports, but you get the idea.
• This was never a problem on my old router.

@Fae 

• TL-R605 is configured directly; no Omada controller connected at all.
• TL-R605 is in DMZ from my WAN modem, so no firewall in effect.  As stated previously, the TL-R605 has replaced an old router that had no problems forwarding the IP camera ports in the same network configuration.