Short summary clearly: I do not connect to domains(+SSL) from internal network (only connect if I add to hosts static entries WAN IP second router). External everything works.
EDIT: Your router likely doesn't support "NAT Reflection", also called "Hairpin NAT" or "NAT Loopback". This means that the requests to your public IP address from inside your own network are either not sent to the server at all or are sent to the server with the wrong "Respond-to" IP address, causing "Triangular Routing" which your computer can't handle. Your router may have a setting that allows you to turn on NAT Reflection. Otherwise, the only way to solve this is with "Split DNS" - setting up DNS in your network to return your server's private IP instead of its public IP.
!!This means 3 routers NOT support 'NAT Reflection' only 1 MikroTik.
Server machine: - OS: Debian 9.3 - Webmin version: 1.872 - Virtualmin version: 6.02 - Usermin version: 1.732 - Server: NGinx with Phusion Passenger (Ruby On Rails) - All installed packages are up to date
-- Business client hotel network setup is 4X ROUTERS:
First router ISP O2 HG622u gateway - public IP xx.xxx.xx.xxx
open DMZ > WAN TL-WR1043ND (static IP)
LAN port to WAN Mikrotik LAN port to WAN TL-WR1043ND
LAN to WAN TL-WR841N / TL-WR841ND
Virtualmin is behind TL-WR1043ND
open 80, 443, 993, 465, 5222, 5223, 5269
From external net everything works (http, https, imaps, jabber)
BUT If I'm at the local network:
a) on net first router get only domains with screen login to admin gateway HG622u for every domain.
b) on net second router get only domains without SSL only http
If I add to laptop /etc/hosts at network on first or second router IP adress from WAN TL-WR1043ND everything works.
HOW to get to see the same(+SSL) domains on both local network as on the external network, without add data to /etc/hosts.
Note: If I setup clear nginx (6 domains) + dnsmasq without virtualmin, everything works internal, external.
Note2: WE love Virtualmin and support open source software and other our VPS and dedicated machines in other countries with Virtualmin works perfectly.. this is first machine with internal (wlan, lan) - external network for clients.
Thank you for Your response!