Re: Routing problems with two public NICs

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

"Oscar Gunnarsson" <oscargunnarsson@xxxxxxxx> wrote in message
news:%239V3OTDWIHA.3400@xxxxxxxxxxxxxxxxxxxxxxx
I am administrating a Windows 2003 server with two NICs which both have
public IPs.

The IPs have the same ISP and are using same default gateway.

NIC1: aa.bb.cc.12
NIC1 (default gw): aa.bb.cc.1
NIC2: aa.bb.cc.13
NIC2 (default gw): aa.bb.cc.1

NIC1 is supposed to serve only as a webserver and NIC2 for administration
purposes and some development.

It seems however that corresponding incoming traffic to NIC2 is outgoing
from NIC1.

I have been informed that it is possible to use static routes for NIC2 to
enable, for example, VPN-traffic to pass through NIC2 instead of NIC1
(which is the case now).

Is static routes the only solution? Or is it possible to define that
incoming traffic also has to be routed out from the very same NIC?

A Static Route might force a certain destination to go out a particular
interface, but there is no point or benefit in doing what you are doing to
start with. There is no bandwidth benefit and there is no security benefit
and it runs contrary to the way networking systems are designed to work.

Networking systems are built to work like this:
1. Each physical Nic is supposed to be a separate subnet (except for Nic
Teaming).
2. IP#s from the same subnet are supposed to be bound to the same physical
Nic (except for Nic Teaming).
3. All Default Gateways need to be on the same Nic and be located within the
same subnet. Typically there should be only one Default Gateway,...if there
are more it follows the Dead Gateway Detection algorithm.

128978 - Dead Gateway Detection in TCP/IP for Windows NT
http://support.microsoft.com/default.aspx?scid=kb;EN-US;128978

171564 - TCP/IP Dead Gateway Detection Algorithm Updated for Windows NT
http://support.microsoft.com/default.aspx?scid=kb;EN-US;171564


--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------


.

Relevant Pages

  • Routing problems with two public NICs
    ... I am administrating a Windows 2003 server with two NICs which both have public IPs. ... NIC1 is supposed to serve only as a webserver and NIC2 for administration purposes and some development. ...
    (microsoft.public.windows.server.networking)
  • [PATCH 2.6.18] PCI: optionally sort device lists breadth-first
    ... New Dell PowerEdge servers have 2 embedded ethernet ports, ... labeled NIC1 and NIC2 on the chassis, in the BIOS setup screens, and ... kernels name these eth1 and eth0 respectively (backwards from ... On systems where, for physical routing reasons, NIC1 appears on a ...
    (Linux-Kernel)
  • Re: NIC War
    ... external requests coming in weren't going anywhere. ... nic1 and nic2 are on the same machine ... "who-has ipA tell x.x.x.x" ...
    (Debian-User)
  • Re: NIC War
    ... > nic2: ipB, macB ... > On the network attached to nic1 one you send an arp request: ... nic2 responds with: ... first nic, and in that case, though it worked, outside requests were not ...
    (Debian-User)
  • Windows SBS 2003 not routing network traffic
    ... I have a SBS 2003 server with two NICs installed. ... I have a router on NIC1 with an IP Address of 10.0.1.1 ... On NIC2 I have a wireless accesspoint with IP of 10.0.2.2. ... the 10.0.2.0 side to be able to talk to the adsl router so they can ...
    (microsoft.public.windows.server.sbs)