Extending a small LAN

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We connect to the world through a DSL modem which by necessity is
located in the centre of our facility. This modem has four LAN ports.
There is a Cat5e line running from one of those ports (LAN1) about 10
metres to our work-room where it connects to the WAN port of a router
which links the four computers and two printers on our LAN. In the
opposite direction from the modem runs another ethernet line (from LAN2)
about 8 metres to an individual workstation.

The modem gets its WAN address from the ISP, obviously, and its LAN
address is fixed at The LAN address of the individual
workstation is and the WAN address of the router in the
main room is The LAN address of the router is
and the six units connected to it are .2, .3, .4 etc. The sub-net for
everything (except the WAN side of the modem) is DHCP is
off in both the modem and the router.

All the computers can get out to the internet. The four computers
connected to the router can all print to both printers and move files
amongst themselves.

What I want is for the individual workstation which is not connected to
the router (and can't be, because of the distance involved and layout of
the office) to be able to print and share files with the devices in the
main room, i.e., for it to be on the same LAN.

How do I configure the router (and/or the modem) to be able to do that?
I've been experimenting with various IP combinations but so far all I've
managed to do is lock up the modem twice! (Fortunately the 'reset'
button sorted that out.) I also tried linking the individual workstation
and the router through a pair of PowerLine devices but the speed hit
(compared to the wired gigabit ethernet link) made web browsing
unacceptably slow for the manager using that computer.     :-(

Thanks in advance for any advice.



Re: Extending a small LAN
Per Henry:
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This is from somebody who does not much about LANs and/or TCP-IP.

Having said that...

My solution has always been to add something called a "Switch".
In my case, 4 Switches that I can think of off the top of my head.

Router ==> Switch ==> multiple PCs and other devices (including printer
and other switches)

In fact, to keep it simple for me (not having any grey matter to spare)
I have only two connections to my router:  Internet and a switch.

Everything else (including more switches) is connected to that one
router-attached switch.

The only thing the Router is really needed for is traffic to/from the
outside.    That being true, the topology just described keeps my LAN up
and running even if the Router bites the big one.

If you go this route, don't chince out on the switch(es): get gigabit
and get switches with at least twice as many ports as you think you will
Pete Cresswell

Re: Extending a small LAN
On 11/26/15 6:05 AM, Henry wrote:
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Simplest thing to do is replace the router with a Ethernet "switch".

That way all PCs & printers would be on the same 192.168.10.x network.  
(Switches themselves do not have an IP address, unless they are  

This assumes you are not using the router also as a WiFi access point  
. If so, move the router to the modem, and connect the switch and the  
lone PC to it.

Re: Extending a small LAN

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Thanks, Retired. It was as simple as that.

We previously had cablemodem service with a very basic modem: one coax
input, from the video cable; and one RJ45 output. So we needed a router.
Then the ISP changed us to this VDSL modem, with, apparently, a router
built-in. Don't need two routers, no.     :-)

cheers, all the best --


Re: Extending a small LAN
Per Henry:
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It can be useful to distinguish between "Router", "Switch" and "Modem".

Just to make matters confusing, most Routers contain both a Switch and a
Router.... and many (but not all....) cable modems contain a Modem, a
Router, and a Switch.

Pete Cresswell

Re: Extending a small LAN
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Sometimes it is nice to have two routers, the usual reason being that
you have some hosts, like the workstation you mention, that you don't
want to have access to the other network.

One reason for NAT routers is to not allow such access.

Some can be configured as more conventional (not NAT) routers.

But your solution is probably the right one.

-- glen

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