@ObjectiviTea ,

Don't know about blocking, but I located this for allowing ports to be forwarded:

https://portforward.com/tp-link/archer-c5400/

Hope this helps.

@ObjectiviTea 

On most TP-Link router port forwarding is called Virtual Servers On the C5400 this feature is located on Advanced - NAT Forwarding - Virtual Servers

@Carl Hello Carl. Thanks for the reply. I do not mean port forwarding. What I mean is firewall port "allow" and "block". Because, without blocking port 53, parental control settings mean nothing, as every kid or guest knows about VPNs. All they have to do is download a free app like Aloha, and they can bypass all DNS control. If there is a router that does support that, then I would like to buy that, but otherwise I am going to have to look at other routers or managed switch solutions. I appreciate your feedback.

@ObjectiviTea 

Okay I understand now thank you for the clarification. No we do not have a SoHo/Home classed router with that ability.  Our Firewall software in these routers is ALG and SPI based so there is no way to block a specific port.  You would need a external fireall or a smart or managed switch connected to the TP-Link router and create an ACL to manage that task.  

One other option could be a "Net-Nanny" software applied to the child's device.  This could act as a software firewall/parental control and disable the possiblity of a VPN software.  Cost wise it might be a valid option.  

Sorry we couldn't be more help.