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Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Connecting two routers wired - the definitive answer

[ Edited ]
This is a common issue and I answered the question probably more than a hundred times thus I put it into a new thread to which I can simply link from now on... Please do not post a reply in this thread if you have a problem setting it up. Post a NEW thread instead. This thread would explode if everybody would post in here...

You have one router running in your network. This router connects to the internet. Now you want to hook up a second router (e.g. a wireless router to have wireless access) in your network connecting both with an ethernet cable. The following is in most cases the best approach for home networks. You'll find similar answers with some screenshots in the Linksys Easy Answers, e.g. 4579

The setup:

1. Unplug the second router from anything. Connect a single computer to the router. Do not connect the second router to the first at the moment!

2. Configure the router at http://192.168.1.1/

3. Change the LAN IP address of the second router from 192.168.1.1 to a free address in your LAN (e.g. 192.168.1.2 should be O.K. if the first router is also a Linksys router). The address you change to (192.168.1.2) must not be used by any other device with static IP address in your network nor should be assigned by the DHCP server your network. A default Linksys router uses 192.168.1.1 itself and the DHCP server assigns 192.168.1.100-149.

4. Turn off the DHCP server on the second router.

5. Save the setting.

6. Unplug the computer from the second router.

7. Connect an ethernet cable from a numbered LAN port of the first router to a numbered LAN port of the second router. Do not use the Internet/WAN port on the second router!

8. That's it! If you don't know or don't want to know more about networking you don't have to read the rest here.

What do you have now?

The second router is connected through a LAN port to your existing network. This basically means that the router part of the device is actually not used. So you have a router device that you don't operate as router in your network. Whatever you connect to the second router either through one of the remaining LAN ports or through a wireless if it has one, is directly connected to your LAN. Devices connected to the second router use the DHCP server of the first router to get an IP address. They use the first router directly for internet access. Everything is connected to a single larger ethernet network. Everything is in a single "broadcast" domain.

If the second router is not a wireless one, you basically have a few more ports in your network. In that case it might have been cheaper to get a simple switch/hub instead to extend your network.

Please remember: as the second router is not connected through the Internet/WAN port many configurations and functions of the second router won't work simply because they require an internet connection on the router itself. Some examples are: access restrictions, dynamic DNS service, port forwardings, MAC address clone, the firewall... All these things must be configured on the first router and only there.

Why is this better than connecting the second router with the Internet port?

A router is a separating network element. It separates two networks and allows certain traffic to cross. Sometimes this is necessary in a network setup but for most home networks it only creates a lot of obstacles.

1. In default Gateway mode the second router does network address translation (NAT). This means computers connected to the second router can connect to computers connected to the first router but not in the opposite direction.

2. If you use Router mode on the second router: you have to configure "routes" on the first router and possibly your computer connected to the first router so that IP packets find their way into the subnet of the second router.

3. You have two separate ethernet networks and thus two "broadcast" domains. A broadcast in the first router's subnet reaches all computers connected there. The same applies to the second router. A broadcast will never cross the second router, though. This is an obstacle for applications that depend on broadcasting to locate other computers and services. Windows file and printer sharing is one example here. With the second router in between, computers on one side do not know about computers on the other side. You cannot search your workgroup for the computer on the other side even when they use the identical workgroup name. You will be able to access the other computer using the IP address directly (e.g. \\192.168.1.100\share) but that's usually a hassle and the IP address may change if it is assigned by the DHCP server to the computer. There are ways to deal with some of these issues (e.g. save the host names in lmhosts files...) but all this requires more effort and attention to keep everything up-to-date.

4. Port forwardings become more complicated. If you need a port forwarding (i.e. you want a port on a computer in your network to be accessible from the internet) on a computer connected to the second router you have to setup two forwardings: one on the first router to the second router and one on the second router to the computer.

5. If you have two wireless routers: you cannot roam between both routers without loosing the connection. This is simply because if a wireless computers moves from one router to the other it needs a different IP address.

6. The whole configuration becomes more complicated: you always have to think about where to configure what, e.g. dynamic DNS service, access restrictions, ...

Bottom line: unless you have good reasons why you must have some computers separated from the other computers in your network, there is no good reason to in a home network to do so. For normal home networking with simple to use file and printer sharing it is better to connect the second router as suggested in this post...

Message Edited by gv on 08-11-2007 01:45 PM
et1212
Posts: 2
Registered: ‎02-18-2007

Re: Connecting two routers wired - the definitive answer

Excellent information. Thank you for taking the time to explain why we should do it this way.
 
One question, though:
 
Why didn't we need a cross-over calbe to connect the 2 hubs? In the old days, we need an uplink port or a cross over calbe to link 2 switches together. How come we don't need to do so for connection 2 routers?
 
Thanks again.
 
 
sharkbyte
Posts: 1,330
Registered: ‎10-09-2006

Re: Connecting two routers wired - the definitive answer

That is because the newer devices are on auto-sense now... that is they can now differentiate the difference between straight through and cross-over cables. :smileyhappy:
et1212
Posts: 2
Registered: ‎02-18-2007

Re: Connecting two routers wired - the definitive answer

Thanks for the quick reply. That is what I figured but could not be sure. I guss only the old timers who have not kept up with the technology still remember such things about uplink ports and cross-over cables,.
 
Posts: 1
Registered: ‎07-31-2007

gud afternoon mam/ sir..   i bought my first  wireless ro...

gud afternoon mam/ sir..
 
i bought my first  wireless router WRT300N for my 4 wired computers and 5 wireless computers then i buy LINKSYS cable/ DSL router model no BEFSR41 but ive got a problem in connecting my second router to my first router because i cant connect all the computers under my second router which is the LINKSYS cable/ DSL router model no BEFSR41  can you send me the step by step to configure the two routers? thanks sir
bpsanborn
Posts: 1
Registered: ‎08-05-2007

Re: I still can't get my WRT54GS to Act as Dumb Hub

I have tried all the advice I can find and to no avail.  I even got my Network Certified Tech son to advise me.
 
I have a WRT54GS Wireless router that was my main and only device acting as a gateway hosting my cable modem access to charter.net.  It is located on the second floor of my house next to my main hardwired PC and print server attached HP Laserjet printer.  I am kicking Charter out and have had Verizon FIOS fiber optic service installed.
 
Verizon supplies an customized ActionTec wireless gateway/router with the install and it is installed in the basement on the same panel as my big circuit breaker panel.  They imply that it must the first router connected to their ONT (Optical Network Terminal)... sort of an optical modem.   I want the devices connected to my Linksys router in the 2nd floor bedroom to be on the same network as the wireless router in the basement. 
 
Based on this forum's and son's advice I did the following to my WRT54GS:
 
1. Changed the its address to 192.168.1.254 subnet 255.255.255.0
2. Turned off the DHCP server function.
3. Set operation from GATEWAY to ROUTER
4. Turn on Dynamic routing for LAN/WIRELESS
5. Plugged a standard cat5e cable from PORT 1 of the Verizon Router to PORT4  of the 2nd floor WRT54GS.
 
Result:  absolutely no connectivity between the Verizon gateway and the 2nd floor and vis-versa.  My 2nd floor PC could talk to the printer on the WRT54GS.  The Verizon router could connect with a temporally hard cabled laptop and with two wireless laptops.  I then tried the other variation of:
 
1. Changed the Ethernet cable from the Verizon Gateway from PORT 4 to the WAN port of the WRT54GS.
 
Result:  Same.. no connectivity between the Verizon gateway and the WRT54GS.
 
I was trying to get the WRT54GS to act as a simple hub and a wireless access point on the network.  I finally gave up and bought a simple $19 hub and everything worked immediately.
 
I still want to put the WRT54GS back in service but I can not make it work.  Whats going on here??
 
Brian Sanborn
 
Groton MA
 
 
 
 
okiecap
Posts: 2
Registered: ‎09-20-2007

Re: Connecting two routers wired - the definitive answer

WIll the ethernet traffic that originates and terminates on devices that are connected to the second router stay/route thru the second router only? I have a particular requirement to keep the traffic from routing thru the 1st router because the powerline connection between the routers is not fast enough to support my streaming video traffic.   Specifically, if I can keep the ethernet traffic between the NAS storage device and the media player (both attached to router number 2) it should work fine.  If I could do this while still having visibility to the computers off router number one, it would would be a bonus. 
neax
Posts: 2
Registered: ‎01-20-2007

Re: Connecting two routers wired - the definitive answer

[ Edited ]
What would I name the SSID of the 2nd router?
 
Would it be the same SSID of the 1st (main) router/gateway or do I / should I make the 2nd one a different SSID?


Message Edited by neax on 09-20-2007 02:41 PM
neax
Posts: 2
Registered: ‎01-20-2007

Re: Connecting two routers wired - the definitive answer

Update.
 
Connecting two WRT54G routers worked fine for me.
Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: Connecting two routers wired - the definitive answer

oki, the switch on the second router should directly send traffic between the devices connected to the second router. The only traffic that will leave the second router is:

* traffic targeted at devices on the other router including the internet gateway

* broadcast traffic

neax, for a single roaming wireless network with two wireless routers connected like I have suggested in this thread, assign the identical wireless settings on both routers except for the channel number which should be at least 5 apart (e.g. 1&6). You should then be able to roam between both wireless routers without loosing the connection.