Re: linux as router

From: Steve Horsley (steve.horsley_at_gmail.com)
Date: 11/09/05 

Date: Wed, 09 Nov 2005 20:29:35 +0000

Adam KOSA wrote:
>> eth0 ip= 10.223.29.1 nm =255.255.255.0
>> eth0:1 ip=10.223.30.1 nm=255.255.255.0
>> eth0:2 ip= 10.223.31.1 nm=255.255.255.0
>>
>
> I'm missing something. You use ip aliasing. This means that all ip
> traffic is coming on the same wire. You would have to use vlan trunking
> for this to work perfectly. I don't see that in you configs. This
> probably means, that you have all subnets in one wire. If you do, then
> i must ask: what is the purpose of having three /24 subnets? Why not
> put all workstations in one subnet and eliminate the need for the
> router? Why don't you shorten your network mask from /24 to /19? This
> would place all three subnets in one: 10.223.0.0 - 10.223.31.255. No
> need for a router.
>

It would also then involve reconfiguring every PC, and would
break connectivity to every other /24 subnet in the rest of the
corporate network that you had also incorporated into the larger
subnet. Then there are issues with some routing protocols not
supporting VLSM.

You don't need VLAN trunking for this to work - it is a fairly
standard setup when a site has outgrown the /24 subnet it was
originally assigned. The PCs can NOT talk directly to each other
because they _expect_ to talk to a router - their subnet mask
tells them to do that.

Steve

Relevant Pages

  • Re: subnets and subnetting
    ... -- or have DHCP do it I presume) to know about the subnet. ... the same wire as the facility in town B. ... a 255.255.252.0 network mask - allowing 1022 hosts on each subnet. ... into chunks with no more than 70 workstations or 4 servers or one router ...
    (comp.os.linux.networking)
  • Re: Client configuration for multiple DHCP scope
    ... The Hosts would be "subnet agnostic" meaning the Hosts would not care what ... Since VLANs have been invented the reason for a Multi-Net to exist has ... physical wire but the VLAN technology separates the physical "wire" into ... technology and the Superscope feature of DHCP could potentially be dropped ...
    (microsoft.public.windows.server.networking)
  • Re: linux as router
    ... You would have to use vlan trunking ... that you have all subnets in one wire. ... broadcast traffic and some devices don't like a lot of pointless broadcast ... that's neither 255.255.255.255 nor the broadcast address for their subnet. ...
    (comp.os.linux.networking)
  • Re: three nic routing with windows server 2003
    ... the default gateway directly ("on the wire" as we used to say). ... default gateway of a workstation must be the router interface in the same IP ... subnet as the client. ...
    (microsoft.public.windows.server.networking)
  • Re: 2 NIC SBS2003R2 LAN/WAN Firewall Router Connection Failure
    ... I changed the SBS external IP settings as you suggest. ... Clients and the SBS Server can reach the router. ... may be there are some rule deny the access from some IP addresses or subnet. ... |> Two Nics, a static IP address, ISA, router ...
    (microsoft.public.windows.server.sbs)