Connecting an host with a subnet to a LAN with different subnet

Connecting an host with a subnet to a LAN with different subnet

[DI BACCO ANTONIO - technolabs]

 
I have a LAN with a given subnet, let us say: 192.168.0.0/24  with a lot
of hosts. Now I want to connect another host (PLUTO) with an interface
that has  address 10.10.10.1 and netmask 255.255.255.0. I can't change
this ip address but I want to insert some iptables rules on PLUTO to
translate both source and dest ip address of the packets it receives to
subnet 10.10.10.0/24 and viceversa. I think that target NETMAP can help
me, but I'm getting confused.
 
Bye,
Antonio.

Re: Connecting an host with a subnet to a LAN with different subnet

[bsilva]

There may be subtlties to your problem that this solution cannot address,
but a simpler solution and one that I've used many times is to give the
machine a secondary IP address on the same interface.

i.e.  "ifconfig eth0:1 192.168.0.x"

Then both addresses are present on the system.


Regards,
Brad


On Wed, 27 Aug 2008, DI BACCO ANTONIO - technolabs wrote:

>
>
> I have a LAN with a given subnet, let us say: 192.168.0.0/24  with a lot
> of hosts. Now I want to connect another host (PLUTO) with an interface
> that has  address 10.10.10.1 and netmask 255.255.255.0. I can't change
> this ip address but I want to insert some iptables rules on PLUTO to
> translate both source and dest ip address of the packets it receives to
> subnet 10.10.10.0/24 and viceversa. I think that target NETMAP can help
> me, but I'm getting confused.
>
> Bye,
> Antonio.
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter" in
> the body of a message to majordomo@vger.kernel.org
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>
>

Re: Connecting an host with a subnet to a LAN with different subnet

[Grant Taylor]

On 08/27/08 13:27, DI BACCO ANTONIO - technolabs wrote:
> I have a LAN with a given subnet, let us say: 192.168.0.0/24  with a 
> lot of hosts. Now I want to connect another host (PLUTO) with an 
> interface that has  address 10.10.10.1 and netmask 255.255.255.0. I 
> can't change this ip address but I want to insert some iptables rules 
> on PLUTO to translate both source and dest ip address of the packets 
> it receives to subnet 10.10.10.0/24 and viceversa. I think that 
> target NETMAP can help me, but I'm getting confused.

Silly question, why not add the 192.168.0.0/24 network to PLUTO?  I.e. 
make PLUTO be multihomed in both the 10.10.10.1 network and the 
192.168.0.0/24 network?

Also, unless you need to map multiple IPs across from one network to the 
other I think I'd recommend that you only NAT the one IP that PLUTO is 
using to avoid potential conflicts.

Even with NETMAP and / or NATing I think you are going to have PLUTO (or 
what ever system does the NETMAP / NATing) have an interface in both 
networks.



Grant. . . .

RE: Connecting an host with a subnet to a LAN with different subnet

[DI BACCO ANTONIO - technolabs]

This can be a good solution but my problem is that PLUTO cannot have the 192.168.0.x address at all.

Thank you,
Antonio. 

-----Original Message-----
From: bsilva [mailto:bsilva@sonic.net] 
Sent: mercoledì 27 agosto 2008 21.04
To: DI BACCO ANTONIO - technolabs
Cc: netfilter@vger.kernel.org
Subject: Re: Connecting an host with a subnet to a LAN with different subnet


There may be subtlties to your problem that this solution cannot address,
but a simpler solution and one that I've used many times is to give the
machine a secondary IP address on the same interface.

i.e.  "ifconfig eth0:1 192.168.0.x"

Then both addresses are present on the system.


Regards,
Brad


On Wed, 27 Aug 2008, DI BACCO ANTONIO - technolabs wrote:

>
>
> I have a LAN with a given subnet, let us say: 192.168.0.0/24  with a lot
> of hosts. Now I want to connect another host (PLUTO) with an interface
> that has  address 10.10.10.1 and netmask 255.255.255.0. I can't change
> this ip address but I want to insert some iptables rules on PLUTO to
> translate both source and dest ip address of the packets it receives to
> subnet 10.10.10.0/24 and viceversa. I think that target NETMAP can help
> me, but I'm getting confused.
>
> Bye,
> Antonio.
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>

Re: Connecting an host with a subnet to a LAN with different subnet

[James King]

On Thu, Aug 28, 2008 at 12:10 AM, DI BACCO ANTONIO - technolabs
<Antonio.DiBacco@technolabs.it> wrote:
> This can be a good solution but my problem is that PLUTO cannot have the 192.168.0.x address at all.

Then your only other option is to add a secondary IP address in the
10.10.10.0/24 subnet on the router for the 192.168.0.0/24 subnet.  You
need to have at least one device numbered in both subnets (although
not necessarily on the same physical interface) in order to route
packets between them.