Server has no internet or computers can't connect

Started by Jon

Hi,

I'm currently trialing bandwidth manager on our Windows Home Server (Windows Server 2003 with some changes). Bandwidth Manager has the potential to provide exactly what we need for our household, but at the moment I'm having major headaches trying to get our setup to work with it.

Our setup is like this:
<internet> <modem/router> <server with two NICs> <switch> <home network>

When we restart the server, the NIC that is connected to the modem/router is the one that shows up with an IP address on the router's status page. At this point the server has internet but our computer can't connect to it to view our files store onto the thing.

On the other hand, if I restart the server with only one NIC connected to the switch, and then plug the modem/router straight to switch, we can acces our files and the server has internet, but obviously we lose the functionality of BWM.

If I then proceed to plug the 2nd NIC from the server into the modem and unplug the modem/router from the switch we can access our files on our homeserver, BWM works, but then the server loses connection to the internet.

Bandwidth Manager is always able to perfectly bridge the 2 NICs on our server, so our network always has an internet connection. However, it's seem like we can either choose to have access to our server but our server loses internet, or we lose access to our server but our server does have internet
SoftPerfect Support forum - Andrew avatar image

Server has no internet or computers can't connect   24 October 2008, 22:17

This sounds like IP addressing issue. To achieve all these things:

1. Be able to access the server's files
2. Be able to access the Internet from the home network
3. Be able to access the Internet from the server

To achieve all of these, you will need to adjust IP settings and/or routing tables.

Let's suppose that your router offers a DHCP service from which all the computers obtain their IP settings and the configured IP range to be given is 192.168.0.50 - 192.168.0.255. Let's also suppose that the router's IP address is 192.168.0.1.

The issue in this case is IP addresses assigned to the NICs in the server. You should assign some unused IP addresses from the same range, for example 192.168.0.2 (NIC1 connected to the router) and 192.168.0.3 (NIC2 connected to the home network). Now you need to tell the server that it should talk to the router via NIC1 and talk to the home network via NIC2. To do so, you need to adjust the server's routing tables, but before you do this, you need to open the advanced Windows TCP/IP properties and assign various metrics to the NIC1 and NIC2: the latter should have lower metric. For example:

NIC1 metric: 30
NIC2 metric: 1

This will encourage the server to use NIC2 to communicate with 192.168.0.x addresses. According to our setup above, all the addresses in this range are connected to NIC2 except for the router connected to NIC1. Now we will add this exception into the routing table (using a command prompt):
route add 192.168.0.1 mask 255.255.255.255 192.168.0.2
(this tells Windows to talk to 192.168.0.1 via NIC1).

Once this has been done, it all should work well. Hope I didn't confuse you even more with this networking stuff smile Feel free to ask further if you need advice or explanation.
Hi,

Thanks for the prompt reply, I'll try what you said, however, a couple of quesitons just to clarify:

In my situation, 192.168.1.254 is the ip address for my router, and 192.168.1.1 or .20 is the address for the server, depending on which NIC shows up. Also, when i do ipoconfig/all in the command prompt, the subnet mask is 255.255.255.0, does that mean I put this subnet mask in rather than 255.255.255.255 that you give in your example? So i'd put in route add 192.168.1.254 mask 255.255.255.255 192.168.1.1 (or 20) ?

When the server is restarted, only one NIC gets an IP address, the other one just stays at 0.0.0.0 and doesn't show up on my router's status page, is this suppose to happen? The softwrae bridge on BWM works perfectly for bridging the modems internet to my other computers though - even if internet is not availabe for the server.

I really appreaciate your help
SoftPerfect Support forum - Andrew avatar image

Server has no internet or computers can't connect   25 October 2008, 03:28

Quote

In my situation, 192.168.1.254 is the ip address for my router, and 192.168.1.1 or .20 is the address for the server, depending on which NIC shows up. Also, when i do ipoconfig/all in the command prompt, the subnet mask is 255.255.255.0, does that mean I put this subnet mask in rather than 255.255.255.255 that you give in your example? So i'd put in route add 192.168.1.254 mask 255.255.255.255 192.168.1.1 (or 20) ?


No, you need to specify 255.255.255.255 as the network mask for the route command. From your example it is still unclear which NIC is assigned which address, and it seems these NICs are configured to obtain IP addresses automatically. I recommend to specify addresses for the server's NICs manually. That is as follows:

NIC facing the router

IP: 192.168.1.20
Mask: 255.255.255.0
DNS: 192.168.1.254
Gateway: 192.168.1.254

NIC facing the home network

IP: 192.168.1.1
Mask: 255.255.255.0
DNS: leave blank
Gateway: leave blank

Now, the route command (which means to talk 192.168.1.254 via 192.168.1.20)
route add 192.168.1.254 mask 255.255.255.255 192.168.1.20

Quote

When the server is restarted, only one NIC gets an IP address, the other one just stays at 0.0.0.0 and doesn't show up on my router's status page, is this suppose to happen? The softwrae bridge on BWM works perfectly for bridging the modems internet to my other computers though - even if internet is not availabe for the server.


Yes, as if both these NICs are configured to obtain IP addresses automatically, one NIC obtains an address from a DHCP server in the router, whereas the second one has got no chance as it is connected to the home network with no DHCP server. I do advise to assign static IP addresses manually to both the NICs anyway as explained above.
It worked!!!!!

Thanks heaps for the brilliant advice!!!
SoftPerfect Support forum - Andrew avatar image

Server has no internet or computers can't connect   26 October 2008, 02:09

I forgot to mention that it may stop working after you restart the server because the newly added route is not permanent. To make it permanent, specify the -p switch:
route -p add 192.168.1.254 mask 255.255.255.255 192.168.1.20

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