2 nics - 2 networks but only one will work

[Guest]

I have a new pc running xp pro with two nics, both manually configured. one
goes to a company intranet (gate ip:10.232.221.65)via an isdn link and the
other to a broadband router (gate ip 10.232.221.75) for general internet
access. The machine will access both networks but only if the other nic is
disabled and vice versa. With both nic's enabled access is only granted to
the route whos gateway appears as the default in the "route print" cmd, any
help?

 

[Interrogative]

I have a new pc running xp pro with two nics, both manually configured. one
goes to a company intranet (gate ip:10.232.221.65)via an isdn link and the
other to a broadband router (gate ip 10.232.221.75) for general internet
access. The machine will access both networks but only if the other nic is
disabled and vice versa. With both nic's enabled access is only granted to
the route whos gateway appears as the default in the "route print" cmd,
any
help?

I'd like to know why the IPs are so similar. I would say one of two things:

1) You need to change the router IP and netmask.

2) If there is a reason that it has to be as is, check the proxy settings.

 

[Guest]

The two gateways sit on the same network, I have tried changing the ips to
10.232.220.75 and also 10.232.222.75 with a subnet of 255.255.255.0 the nic
with the ip of 10.232.221.65 (subnet 255.255.255.224) can't be changed
because its the companies.

 

[Guest]

What do you mean by proxy settings? there are none in the connection options
of Internet expl. Should there be?
Kempi

 

[Doug Sherman [MVP]]

If I understand you correctly, you have an XP Pro machine with 2 ethernet
adapaters - ie one of these adapters is not an ISDN modem or ISDN terminal
adapter. You want to route traffic to the company's intranet through a
gateway device with an IP of 10.232.221.65 mask 255.255.255.224, and you
want all other non-local traffic to route through a broadband router with an
IP of 10.232.221.75 mask 255.255.255.224.

You have three choices in configuring the XP Pro machine:

1. Cable all devices together through the router (or a common switch
connected to the router) and use a single NIC in the XP Pro machine. Set
the XP Pro machine with an unique IP address between 10.232.221.65 and
10.232.221.95. Set the default gateway to 10.232.221.75. Configure a
static route:

route add <network IP of company Intranet> mask <subnet mask of company
Intranet network> 10.232.221.65. Or

2. Do the same as #1 except configure the static route on the broadband
router. Or

3. Use 2 NICs in the XP Pro machine. Connect one directly (or through a
switch) to the 10.232.221.65 device and configure the NIC with an IP address
on the 10.232.221.x/255.255.255.224 subnet. Do not configure a default
gateway on this NIC, and do not connect the 10.232.221.65 device to the
broadband router. Change the IP address of the router to something which is
not 10.232.221.x/255.255.255.224. Connect your second NIC to the router (or
to a separate switch connected to the router). Configure this NIC with an
IP address compatible with the the router's new address and enter the
router's new address as its default gateway. Configure a static route to
the company's Intranet per #1 above.

Note, if the company Intranet is actually on 10.232.221.x/255.255.255.224,
you do not need static routes. If the company Intranet is on some other
network and 10.232.221.65 is only a gateway interface to the remote network,
then you must configure a static route per the above.

Doug Sherman
MCSE, MCSA, MCP+I, MVP

 

[Guest]

Thanks so much for this, but before I try, the broadband adapter has a ip of
10.232.221.75 but a subnet mask of 255.255.255.0, will your solution work
with that?
Thanks again,
Ian Kemp

 

[Doug Sherman [MVP]]

Hmmm.

Well, you could not use a single NIC solution unless the router's mask and
the mask for the adapter on your XP Pro machine was 255.255.255.224.

For a 2 NIC solution, you are likely to have unpredicable results in any
case where applying the subnet mask of one adapter to the IP address of the
other would put the IPs on the same subnet. Where, as here, the respective
masks of both adapters puts the IP of the other on the same subnet, well ...
it might work, but probably not. For a 2 NIC solution my advice would be to
change the router IP to something other than 10.232.221.x and make
compatible changes to the NICs on all devices connected to the router.

Basically, for a single NIC all devices must be physically and
mathematically on exactly the same subnet. For a 2 NIC solution the devices
must be physically and mathematically separated. Mathematical determination
of subnets involves a process called 'anding' in which a computer applies
its subnet mask to a destination IP address. If the calculation results in
a determination that the destination is on the same subnet that the machine
is connected to, the packet is not sent to the machine's default gateway or
any gateways configured for static routes.

Doug Sherman
MCSE, MCSA, MCP+I, MVP

 

[Interrogative]

The two gateways sit on the same network, I have tried changing the ips to
10.232.220.75 and also 10.232.222.75 with a subnet of 255.255.255.0 the
nic
with the ip of 10.232.221.65 (subnet 255.255.255.224) can't be changed
because its the companies.

Then you probably just need to buy (the company buy, more likely) a smart
bridge and have someone set it up for you who knows about them. It will
direct data from your machine appropriately.

Alternatively, you could do one other thing - download Netswitcher. You can
use that prog to switch easily between nets so that you don't have to keep
mucking about. It is actually meant for 2 entirely separate networks such as
your home lan and work lan and switching between them but I cant see why it
wont work in your case.