No access to dynamic dns address from inside local network but ping/tracert works fine

Hi there everyone,

I am running seafile on a raspberry pi 3 with nginx https enabled (lets encrypt) and a duckdns.org dynamic url

Everything works fine when accessing the dDNS url from outside my local network from browser as well as mobile app (android).

When trying to access the same .duckdns.org url from my local network I get a connection timeout.

My guess was that there is not NAT loopback in my router, but pinging or tracert for the url comes back just fine:

Tracing route to ***.duckdns.org [x.x.x.x]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms my.ISPs.domain.and.route [x.x.x.x]

Trace complete.

or is this unrelated to the NAT loopback?

Do you use a Fritzbox as your router? The Fritzbox has a rebind protection so you have do tell the Fritzbox the domains for which the rebind protection should not be used.

1 Like

thanks for the input! It’s not a fritzbox, no. it’s a japanese ISP’s router for their fiber connection (NTT, model: pr500-KI)
I’ll look into that rebind protection, just to be save!

Thank you very much! The Fritzbox DNS rebind protection was indeed an issue for me, I could not connect with the seafile native apps to the dynamic dns address, only the IP address of my self cloud server worked. Now I added exclusions in the DNS rebind protection, the dynamic dns address works flawlessly.