Sharing Single Internet Connection between different subnets

[rajthampi]

Hi guys
I am using linksys BESFR41 V.4 for sharing internet connection among my users. For some specific reasons we've a different subnet within the firm and now I am asked to share the existing internet connection among both subnets & I am wondering how I could achieve this task without putting another router online. Please tell me whether I could configure the existing router to enable Internet connection sharing between two subnets? Else what would be the alternative solution. Since we are using a corporate DSL account, I ain't sure whether my firm would allow me to go ahead for a second Internet connection mainly due to high costs we pay here for the connections.

Thanks in advance
regards

[JamesO]

Easiest way to do this without another router is to put all the machines on the "second" subnet on the network with the DSL connection. Than can be done with an Ethernet switch or possibly an existing router without using DHCP or the WAN port (using the router only as a switch). Probably easier said then done for any of a number of reasons!

If you have 2 separate subnets, you 2 separate networks and probably 2 separate routers. The is probably a reason you have 2 subnets, it might be for security reasons and/or for special software as well.

I think we need to understand how and why you have 2 networks.

JamesO

[rajthampi]

Originally Posted by JamesO

Easiest way to do this without another router is to put all the machines on the "second" subnet on the network with the DSL connection. Than can be done with an Ethernet switch or possibly an existing router without using DHCP or the WAN port (using the router only as a switch). Probably easier said then done for any of a number of reasons!

If you have 2 separate subnets, you 2 separate networks and probably 2 separate routers. The is probably a reason you have 2 subnets, it might be for security reasons and/or for special software as well.

I think we need to understand how and why you have 2 networks.

JamesO

JamesO
Thanks for your reply. Well, we have two subnets to reduce the load on our Citrix, Oracle Servers. We have classified the Citrix+Oracle application users to one subnet and rest of the users [Cad, CRM etc] to another subnet. We are using one simple Linksys BEFSR41 router for routing between these two subnets and everything were working perfect till few of the Citrix users are promoted to use our CRM application recently deployed in the internet. I hope this explanation is adequate for you query.

Thanks once again and regards

[JamesO]

You will either be looking at a more advanced router than a SOHO router or possibly setting up 2 NIC's in some machines so they can access the 2 separate subnets.

The 2 NIC's might be more cumbersome and might require more facility wiring, where the router may cost more up front, but probably take less time to implement and will be more flexible in the long run.

JamesO

[Squashman]

Sounds like you need one big switch that you can setup VLan's on.

[JamesO]

Squashman,

Good suggestion, however, I cannot remember, but will VLAN's allow connections between subnets (minor routing?)?? Have not dealt with VLAN's except, just virtually subdividing a switch.

JamesO

[Squashman]

I have not setup VLAN's since I was in school. I do not remember if you can setup routing between them but why wouldn't they. Seems like a good idea if they did. I will ask one of my friends who is a CCNA.

[rajthampi]

Hi guys

Well my constant search in the net fetched me the following stuff. Please have a look at it.

By "adjacent" offices, do you mean right next to each other (within 100
feet) or across the street?
I will assume they are next to each other.
1) Connect both subnets together using some kind of IP router. You have
many choices here. You can buy hardware based (two ports) routers, such as
Cisco, that will be configured to route IP between both subnets. These
range around $1,500-2,000. BTW - Anyone know of any cheap two port 10BaseT
routers? You could also go with "software" solution, such as RRAS included
in Windows 2000 Server. For the cost of another NIC, you can leverage an
existing server to route between networks.
2) You will need the cable modem/router from your cable provider. They
typically include one with the service and configure it. Depending on the
model, it may also include things like NAT (see next). These devices
usually have one coax connection and one Ethernet port.
3) You will need a NAT or a Proxy server to share your public IP
address(es) with your clients on the two subnets. Here too, you can buy
hardware solutions or software. LinkSys has good one they call "BEFSR11 -
EtherFast 1-Port Cable/DSL Router", and at $89.00, it is hard to beat. You
can also do same thing with RRAS.

So here are two good options. Each assumes cable service and cable modem
installed:
Hardware Option:
Buy two BEFSR11's. Use one as your router between subnets. Use the other
to act as NAT/firewall to share your INET connection. Pretty much done for
~$200 bucks. Nice thing about this solution is that it is "set and forget."
You can also leverage the DHCP service in the routers for your network.

Software Option:
Install 3 NICs in a w2k server. Hook one up to subnet1, one to subnet2, and
one to cable modem 10BaseT port. Install and configure RRAS. This option
is more configurable and flexible. However, setup is more difficult and
relies on server being up all the time.

Cheers!

This literature was posted by a MCSE. Now this portion of note has put new hopes in my requirement. Please find the details of my existing two subnets

First subnet
----------
172.168.2.0/255.255.255.0 and the linksys router is connected to this subnet with a static IP address 172.168.2.99

Second Subnet
-----------
172.168.3.0/255.255.255.0


Linksys router BEFSR41 is properly routed and users from both subnets can access our application servers etc.

As I mentioned with my first post, now my requirement is to share a single Internet connection.
Is it is worth to go for another router and do the routings as that piece of info suggests? Incase if it is really worth, Please suggest me what kind of setting changes I have to do with the first router (equipped with DSL line) and what kind of settings I must do with the second router so that the users from the second subnet would able to access Internet through the first router?

Thanks in advance

[leroys1000]

It seems to me that all you should need is a simple network bridge
to bridge the two networks together.
A windows xp machine can also do this,as it has a built in software bridge.
It will need two network cards,one for each subnet,and can be bridged
in network connections in the control panel.

[rajthampi]

Originally Posted by leroys1000

It seems to me that all you should need is a simple network bridge
to bridge the two networks together.
A windows xp machine can also do this,as it has a built in software bridge.
It will need two network cards,one for each subnet,and can be bridged
in network connections in the control panel.

Thanks for your suggestion leroys! More than just going for bridging the two networks, I would prefer using two routers, based on our new developments which might extend our firm to new branches all over kuwait. Any suggestions?

Thanks in advance
Regards

[JamesO]

Sounds like you might want to start considering VPN connections if you start having remote offices?

With VPN connections this allows access to central file server(s), printer(s), database(s), email, etc. But you still need to sort out how best to access the VPN and allow outside Internet access. This can get rather complex, but decisions need to be made regarding requirements, security and budget.

JamesO