I trying to set up a VPN server that I can connect my homenet when I am outside.

my network use pppoe, so I ty to set up tplinkddns in deco app(lastest version in app store), and set up a L2TP VPN server, but when i connect via iphone or pc it will tell me the L2TP VPN server is no reaction.

hence, i set up noip ddns ,and duc status look all green,so I try to use this ddns setting ,set up a VPN server in deco apps, not working either.

my device

1. iphone 11 ios 18.0.0

2.windows 11 pc 23h2 22631.4317

below is some describe and question

1. I can not set up server via pc 192.168.0.1 or 192.168.1.1 is no reaction.(I already disable my Realtek 2.5GbE Family Controller and connect the deco wifi.) 

I only able to access tplinkdeco.net, but there is no option to set up a server, so I can only set up in deco app. my question is can I set up ddns and VPN server via pc?

2. I can only  connect the VPN server when I connect deco wifi and change the device VPN server setting to 192.168.1.101

I think I have something wrong in ddns setting, but I cannot figure out the problem. Please give me some instruction to set up the server.

Not a native speaker please forgive my poor English .

If my describe is not clear enough or need some further info please tell me, I will provide it as soon as I see the comment, thank you.