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My topology looks like this:

    - Router 1 (LAN;
        - PC 1 (
        - Router 2 (WAN; LAN;
            - PC 2 (

And I need to enable windows file sharing between PC 1 and PC 2. And when I go to "Network" in Win7 Explorer, I want to see my PC 1 and PC 2 there on both computers.

My Router 2 redirects ports 445 and 137-139 to PC 2. This way, I managed to get it working somewhat. I can access the PC 2 from PC 1 by entering IP directly "\\\". But I cannot access the PC 2 from PC 1 by typing it's computer name, and I also don't see it in "Network". It goes the same when accessing PC 1 from PC 2 ... I can use IP, but not name.

I tried using DMZ on Router 2 but that did not helped one bit. I tried turning PC 2 Windows Firewall off, but that also did not helped. When both computers were connected to the same router, it all worked fine. But the topology changed recently. So how can I get it working again? Thanks.

PC 1 is Win7, PC 2 is WinVista.

share|improve this question
Why is your network set up this way?! Why not flatten it? Dual NAT sucks. (Your setup is very broken. How would a packet from to ever get to router 2?) – David Schwartz Mar 6 '13 at 0:54
Because some PCs don't have Wifi and the Wifi router (Router 1) is not accessible by multiple cables. – Paya Mar 6 '13 at 0:56
So why not connect the Internet access to router 2 and use router 1 just as a switch and access point? Or connect router 1's wired port to router 2's LAN port and connect other wired machines to router 2? Or something that makes sense. – David Schwartz Mar 6 '13 at 0:57
Router 1 is also modem, I cannot move it around. To access Router 2 subnetwork, I just need to address Router 2 WAN address ... I need to get running the file sharing and other incoming connections are not required. But I would need to use port redirecting otherwise obviously. – Paya Mar 6 '13 at 1:00
So connect router 2's LAN port to router 1's wired port. Disable router 2's DHCP server. Connect wired machines to router 2's other LAN ports. You will never be happy with a dual-NAT setup. – David Schwartz Mar 6 '13 at 1:01
up vote 1 down vote accepted

Get rid of double NAT. You can use routers as switches and access points by connecting them LAN-to-LAN.

share|improve this answer
Related discussion is in the comment section of the question. – Paya Mar 6 '13 at 21:05

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