I hope there must be some resolution to this. I have the exact reverse of what is commonly the problem. Our small business office recently moved to a new building in a new city. We have a Mac mini running NeXT Cloud. I set things up with our new router (behind ADSL) port forwarding as we need, etc. From outside our network, HTTP, HTTPS, sync services all work well. From INSIDE the lan, nothing works and I can’t even Ping the address. We use dynu dns for hostname resolution, but the IP address behaves the exact same way, so this must be something to do with the router.

Oddly, I am able to access all services using the local IP of the server while within the network. This probably helps point to the solution I am missing. Is there some setting local to the server's network settings that I need to change? Putting the server inside the DMZ and outside the DMZ leads to odd results. Server local address inside the DMZ, nothing works LAN, everything works WAN. Server local address not in the DMZ, everything works WAN, HTTPS to the external IP address works within the LAN, HTTPS to the external IP address works within the LAN, but neither SSH nor NeXTcloud work to the external IP address within the LAN. I find this to be very odd. What would selectively block services like this?

I ran myself ragged doing a systematic and redundant pass through all the settings, adjusting usual suspects like firewalls, and nothing I have tried works.

Any thoughts on how to solve?

  • The proper way to do this is to set up your local DNS to point to the local address, not the public address. You could use hairpin routing, but that unnecessarily burdens your router and its LAN interface bandwidth, both incoming and outgoing. Using the DNS solution will completely bypass the router and keep LAN traffic on the LAN. – Ron Maupin Dec 8 '19 at 14:26
  • Thanks for pointing me in this direction. I'm not familiar with how to get the local DNS to point the dyndns URL traffic to the local address. Any thoughts? I don't see any likely suspects in the router GUI and could enable editing by terminal, but hope I don't have to. My memory fogged from years past tells me there should be a way to map external addresses to internal IPs on the router only. I'm not sure where to look. I'd want for example phones and tablets to be able to keep NeXTcolud settings identical both in WAN and LAN. – David Getzin Dec 8 '19 at 21:29

This has been solved. Ron Maupin was correct. A DNS map of the DYN DNS name to the local IP is correct and works. CAVEAT: anyone using the GUI to a ZYXEL router, the "DNS Host Mapping" settings hava a really stupid and useless "enable" and "disable" radio button that I was overlooking while entering the data. (stvpid design shown) - Click enable, all things work. Thank you. I hope this DNS host mappinghelps others.


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