Re: TCP/IP Cluster Alias question

From: Phillip Helbig (HELBPHI_at_sysdev.deutsche-boerse.com)
Date: 05/02/03 

Date: Fri, 02 May 2003 09:21:53 +0100 (MET)

> I have a cluster running VMS 7.3-1 with TCP/IP services. Each machine
> has 2 network interface cards. The cluster sits on 2 IP subnets. I was
> wondering if it is possible to set up TCP/IP to have a cluster alias
> for each subnet that the computer was attached to.
>
> For example:
> The subnets are 192.168.1.x and 192.168.2.x. On the 192.168.1.x I
> would like users to be able to connect to the cluster alias DSPSRV1,
> and on the other subnet I would like then to connect to DSPSRV2.

As far as I know, if you have two ethernet cards, you have two
completely independent interfaces. I've never tried the setup you
describe, but I would be surprised if it didn't work.

You will run into another problem, though. You have to have a default
route for TCPIP. Outgoing traffic will be routed through the default
route, even if it is "return traffic" from a connection which came in
over the other interface. You can get around this if you know in
advance who will connect to what interface and enter explicit routes for
these addresses.

Another way to use both networks is to have one machine on each network.
I have actually done this. If you have LAT or DECNET running, or if you
set explicit TCPIP routes from one machine to another, you can connect
to either machine from outside, going through the other machine if
necessary.

Another possibility would be to have a NAT router set up in reverse.
Search this newsgroup for a post by JF Mezei on this topic.

Relevant Pages

  • Re: Multiple NICS on same subnet
    ... multiple NICs on the same subnet. ... No packets are *ever* route to this interface. ...
    (comp.os.linux.networking)
  • Re: FC1 multiple ethernet interface issue
    ... >> Here is the dump from ip route list for various modes of the nics. ... > Note that the default route has switched to the eth1 interface. ... of the subnet associated with the router and the interface. ...
    (Fedora)
  • Re: Routing quesiton (maybe specific to Nokia IP130 router?)
    ... If you are asking how to route to a directly connected subnet, ... have to do anything other than configure the router interface. ... To configure the interface; Voyager> IP address, subnet, speed, duplex, ...
    (comp.security.firewalls)
  • Re: route delete not working
    ... It should not be in the same subnet as ... > The route -f did delete the 9.0.0.0 route along with ... > Ethernet adapter Local Area Connection: ... >>>> Interface List ...
    (microsoft.public.windows.server.networking)
  • Re: Cant send packets via WiFi (possibly route issue)
    ... I think that this WiFi device should route all ... it should *all* be routed to the eth1 interface. ... Wireless is much like a point-to-point link using ... The connection between the two networks is the "Wifi AP". ...
    (comp.os.linux.networking)