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This is the first time I am faced with routing and it seems I have hit a dead end. I have the following scenario:

client1:

  • 192.168.1.10
  • 255.255.255.0
  • gateway: 192.168.1.100
  • DNS server: 192.168.1.100

client2:

  • 192.168.1.20
  • 255.255.255.0
  • gateway: 192.168.1.100
  • DNS server: 192.168.1.100

server (Windows Server 2008 R2 with enabled RAS & Routing Services)

network card 1 (connected to a switch along with the clients)

  • 192.168.1.100
  • 255.255.255.0
  • DNS server: 127.0.0.1

network card 2 (connected to the router)

  • 192.168.2.100
  • 255.255.255.0
  • gateway: 192.168.2.1
  • DNS server: 127.0.0.1
  • (DNS forwarding to 192.168.2.1)

ISP router (with connection to internet)

192.168.2.1

Now in this scenario I have tried to route traffic from the 192.168.1.0/24 network with the clients to the 192.168.2.0/24 network with the routers to connect them to the internet. However, no matter what I do I get no positive ping to the router 192.168.2.1.

Ping from 192.168.168.1.10

  • to 192.168.1.20: Success
  • to 192.168.1.100: Success
  • to 192.168.2.100: Success
  • to 192.168.2.1: not reachable

The routing table contains the 2 routes 192.168.1.0 and 192.168.2.0 as directly connected.

Does anyone know where the routing fails?

I have searched different forums but mostly found nothing relevant. One post however pointed out that in a similar situation the problem was that the router doesn't know the way back and the internet router would need a static route back to the first router. If that really is the case, I take it there is no solution with my equipment, because the standart ISP router doesn't allow to set any static routes.

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Why are you doing this? Why do you not just have all of the clients connected to one network? Why are you configuring multiple networks? –  joeqwerty Oct 5 '12 at 20:26
    
Does your gateway device at 192.168.2.1 have a route to 192.168.1.0/24 through gateway 192.168.2.100? Edit: I guess you answered that with your last paragraph. That is likely your problem. –  Doug Luxem Oct 5 '12 at 20:30
    
@joeqwerty this way the clients are behind the server which will have advantages when configuring a vpn later on where the server with it's firewall sits before the clients –  LumenAlbum Oct 5 '12 at 20:40
    
@DougLuxem can you confirm that a static route from 192.168.2.1 to 192.168.1.0/24 would be necessary? is there any way with a RIP protocol on the server or anything else that does not need to be configured on the ISP router? –  LumenAlbum Oct 5 '12 at 20:42
2  
Right. I see what you're getting at. I just wonder if it's too much additional complexity. IMO, your gateway devices (router/firewall or router and firewall) should provide those services for your network. I'm not a fan of using any OS as my network firewall/security device. You can certainly use the server as your RRAS/VPN endpoint but I would suggest using the router for everything else. If the router doesn't have builtin firewall capabilities (ACL's) then I would suggest getting a purpose built firewall. –  joeqwerty Oct 5 '12 at 21:04
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2 Answers

up vote 1 down vote accepted

To summarize the comments -

Your clients on the 192.168.1.0/24 network are unable to reach the Internet or ISP router (192.168.2.1) because that router does not have an explicit route to the 192.168.1.0/24 network through the RRAS server (192.168.2.100).

Possible solutions:

  • Add a static route on the 192.168.2.1 router from the 192.168.1.0/24 network through a gateway of 192.168.2.100.
  • Combine the two separate subnets so they are on the 192.168.1.0/24 (or /23) network, which is local to that ISP router.
  • Have the RRAS server perform NAT on the connections so that the ISP router will see the connections as coming from 192.168.2.100 instead of the actual source.
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It's probably a NAT issue.

You don't need to create static routes because both networks are directly connected to the RRAS server.

So you need to specify the external and internal (where you need to perform NAT) in the RRAS management console.

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