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2 NICs and Default Gateway Problem

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7 replies

by oscarlr

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HI:
I have a problem with my w2k server, I work with 2 Network Cards from different LANS
For example:
NIC 1 IP 10.0.2.8
Gateway 10.0.2.12
NIC 2 IP 10.0.6.8
Gateway 10.0.6.12
When I use the commands ROUTE PRINT I check the default gateway is from the NIC1 (10.0.2.12), but suddenly (3-6 times at day) it changes to gateway of the NIC2 (10.0.6.12)
I want to know how can I kept the default gateway of NIC1, or which is the reason of the change.
Best Regars

7 replies

by joseph moore

Well, use the /P switch to make a Route Add command permanent. Here is an example from the help file of Route:

route ADD /P 157.0.0.0 MASK 255.0.0.0 157.55.80.1

This is adding a a route from 157.0.0.0 to 157.55.80.1 and with the /P it is making the route permanent.
So, try adding your route for NIC1 to its gateway, and make it permanent.

Hope that helps.

by mcarswell

Segment1(10.0.2.*) => Nic1(10.0.2.8) | (10.0.6.8) Nic2 <= (10.0.6.*) Segment2

If you are not routing between the two network segments that you should just have one gateway on one Nic.( If you have a router that routes to multiple subnets then theNic on that subnet should be set up with the GW as the IP Address of that Router and all other nics should be left Blank). All the client on the 1 Segment 10.0.2.* will communicate with the 10.0.2.8 card with out having to be routed to the GW and this also applies to the computer on the 10.0.6.* segment they will communicate with the 10.0.6.8 Nic. As far as the server is concerned it will communicate out of the Nic that is on the local subnet of the PC that it wants to establish connection with.

by oscarlr

Im not routing with this server.
I has MS Proxy in this server.
The problem that I have is when users from other segments are trying to connect to the internal address.
Mi external internet address is 10.0.2.8 and it?s gateway 10.0.2.12Mi internal address ins 10.0.6.8 by default no gateway.
But I have another WAN segments 10.0.8.x and they cannot connect to the proxy server addres 10.0.6.8 because this nic doesnt have any gateway. To solve this I define the gateway for 10.0.6.8 with gateway 10.0.6.12 and works!!!
But suddenly the server changes theier default gateway and I cannot route accross the proxy to Internet.
Can you help me???

by mcarswell

question.

1 subnet = 10.0.6.*
client on 1 subnet have the following GW 10.0.6.12

2 subnet = 10.0.8.*
client on 2 subnet have the following GW 10.0.8.12

External GW to the Internet = 10.0.2.12

if all of this is true Your proxy server should be configure using as the following

You will need to have 2 IP address on the Internal nic which will represent the gate way of both Subnets:
IP = 10.0.6.12
IP2= 10.0.8.12
GW = BLANK

The external Nic will have the following IP and GW
IP = 10.0.2.8
GW = 10.0.2.12

Try This. I have a diagram if you send me a email I will forward it to you it is in Visio 2000 Format but i can export it to a format of your choosing

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