Now I'm looking for more information why do my network file sharing doesn't work properly even if I made router to be part of LAN. I'll explain all my possible changes I can remember. I chosen to merge both of devices into same subnet.
Modem has DSL connected so internet is available.
PC1 <-LAN-> Modem <-LAN-> Router <-LAN-> PC2
LAN IP: 192.168.1.1
DHCP: ON (Range: 192.168.1.2 - 192.168.1.-199)
LAN IP: 192.168.1.200
DHCP: ON (Range: 192.168.1.211 - 192.168.1.254)
I want DHCP it to be enabled, because only 200-210 ending addresses will be static ones. Rest of users are friends or such.
PC1 (Connected to Modem)
PC2 (Connected to Router)
All what I have noticed
Router is pure-NAT router and NAT cannot be turned off for some reason. There's no such a option. (TP-Link WR940N)
I see the both of devices on explorer's Network section (PC1, PC2), but they can only connect to themselves, but not each others.
Both are on Private network profile and both has folder shared which has permissions to "Everyone - read & write"
Both have access to internet too.
Logging into Modem's Administrator Web-UI I can see both of devices as clients in client list: (PC1 - 192.168.1.205, PC2 - 192.168.1.206)
Explorer says from PC1: "Windows cannot access... Problem can be in network", but I cannot find any problems in my configurations. Private network file and printer sharing is turned on.
Many people may think why do I have router between modem and PC2. Actual reason is that I like to play with devices and I want to learn much more about them.