Connecting a Switch to a Router

[rsr207]

I'm trying to connect a Linksys 10/100 8-port workgroup switch (Model EZXS88W) to a Comtrend Wireless ADSL2+ Router (Model CT-536+) and its not working. Linksys support says the switch is just a pass through device and if its not working then I should just return it (before I waste the gas on another trip to the store I thought I'd try to get a second opinion :)

I've tried to connect the switch by connecting port 1 to one of the pc ports on the router and by connecting the uplink port on the switch to one of the pc ports on the router. Neither worked.

I did get an IP address conflict error on my computer. I have a static IP address b/c I'm running a server too...could that have something to do with it?

Any ideas much appreciated.

[DMR]

... and its not working.

Well now, that certainly gives us a lot to go on... :mrgreen:
Please give us as many details as possible on your IP addressing scheme as a whole, what exact errors you've encountered, etc.

As far as the switch goes, the EZXS88W is nothing fancy, and there aren't any special configuration settings or the like involved with that device AFAIK. The only thing to keep in mind is that when using the uplink port on that switch, the normal/PC port directly adjacent to the uplink port becomes disabled; the two physical ports are shared internally, so the uplink and PC connections cannot both be used at the same time.

[rsr207]

Laugh...sorry, when I connect the switch to the router and then reboot both of them the lights on router's ethernet ports would flash quickly and never be able to hold solid and so i wasn't able to connect to the internet at all (hence it's not working) :)

The only thing I know about my IP addressing scheme is that I have a static IP address assigned b/c I'm also running a MS XChange server here. I got in touch with my tech guy yesterday who set it up for me (he moved, so I'm trying to figure out as much as I can on my own and only call in case of emergency!) and he thinks its a bad switch as well...so I'm off to the store today and if it doesn't work with the second one, I'll be back...

[DMR]

... the lights on router's ethernet ports would flash quickly and never be able to hold solid...so I'm off to the store today and if it doesn't work with the second one, I'll be back...

Ok- hopefully it's just a duff switch, but if the new gives you problems too, we'll be here... :)

[rsr207]

Ok- hopefully it's just a duff switch, but if the new gives you problems too, we'll be here... :)

sigh...so I'm back. Not a bad switch, new switch...same problem. When I hook up the switch to the router I get this error on my computer:

"Local Area Connection Status
Limited or no connectivity.
You might not be able to access the internet or some network resources. This problem Occured because the network did not assign a network address to the computer."

It gave me the option to fix it, and it did for a second. It said:

Address Type: Assigned by DHCP
IP Address: 192.168.1.8
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1

I checked my other computer that was hooked up throught the switch and it never was able to connect...it said:

Windows System Error
There is an IP address conflict with another system on the network

With the switch plugged into my router, all the lights on the router start flashing quickly, as soon as I unplug it, they go back to solid and everything works fine.

Is there any way I'm going to get this switch to work on my LAN?

[DMR]

Um... hang on here- just how many computers do you have on this LAN, and out of those, how many existed "pre-switch installation"?

The error messages you've posted are what you would expect on a network in which the computers are using a mix of dynamically assigned (DHCP) and statically assigned IP addresses, but where the scope of IP addresses handed out by the DHCP server (the router, in your case) overlaps the range of static IP addresses you've chosen.

As an example: You have a network (with or without a switch; the switch really is transparent here) in which the router is configured to assign computer IP addresses via DHCP from the private IP address range of 192.168.1.1 -> 192.168.1.50.
However, you also have 2 computers on that network which you have manually (statically) configured to use the IP addresses 192.168.1.7 and 192.168.1.8. In this scenario, the router has no way of knowing that the IPs 192.168.1.7 and 192.168.1.8 addresses are already in use, and, as those IPs are within its DHCP scope, it tries to assign those IPs to other computers on the network. Since each computer on the network needs a unique IP address, you can see where/why the conflicts occur.

Assuming I'm shooting somewhere close to the bull's eye here, you have two options:

1. Don't use DHCP at all; just configure all of the computers to use static IPs. For smallish networks this is the simpler way to go, although it gets too cumbersome if you have more than 20 or so computers.

2. Reconfigure the router's DHCP scope to use IP addresses which still fall within the same 192.168.1.x network range, but which fall either above or below the range of addresses you've currently used in your static assignments.

[rsr207]

Wow...not sure how you did that, but I think you hit the bulls eye. I'll decide which way to go tomorrow and let you know how it works out...

To ans your ques re how many PCs, I'm merging 2 home offices hence the need for the switch.

At this location pre-merge...MS Xchange server, PC, 2 vonage adapters on the router and usu 1-2 laptops connected wirelessly

Now with the merge:
I've added a wireless range extender and am hanging another pc off of that.
And with the Switch I'm attempting to add another PC and 3 more Vonage adapters...welcome to my madness :)

[DMR]

Thanks for the info- that explains a lot. Madness indeed; I feel for 'ya. :mrgreen:

With the network configuration you've outlined, it sounds like you'll want to retain the DHCP functionality if for nothing else than the ease of connecting the visiting/floating laptops to the LAN. If so, I'd suggest going the route (no pun intended, of course) of configuring the router's DHCP server settings to use a range (scope) of IP addresses that don't conflict with any IPs that you've manually assigned.

With a network range of 192.168.1.x and a subnet mask of 255.255.255.0, one common configuration is to set the starting address of the DHCP server's scope to 192.168.1.100, and to then assign all static IPs working from 192.168.1.1 (usually used/reserved for the router itself) up to 192.168.1.99.

[rsr207]

I think the problem is solved...turns out the culprit was one of my Vonage adapters...I was plugging 2 ethernet connections from one of my Vonage adapters into the switch thinking they were 2 phone lines, but one was actually a PC port and meant to be plugged downstream into a PC. Apparently the Vonage adapter has some DCHP Server functionality (unlike the switch which was and is in fact a pass thru device) and that was creating the IP conflicts...

Thanks for all of your time/help.

[DMR]

Apparently the Vonage adapter has some DCHP Server functionality...

Correctomundo!
If you've got Linksys RT312Ps, those are full-blown routers in and of themselves (the "RT" in Linksys product lines indicates "router"), so they can definitely act as DHCP servers. As a matter of fact, DHCP is active by default on those devices, at least the ones I've installed.

Good troubleshooting; glad you got it sorted :)
Does everything appear to be happy in IP Land now? If so, I'll mark this topic as "solved".

<EDIT>

I'll throw this link from Vonage's site in here just for reference; it contains info and instructions on connecting vonages devices in different network environments:
http://www.vonage-forum.com/setup.html

</EDIT>

[rsr207]

Solved...muchos gracias

[DMR]

Cool- then marked as solved she be... :)

[sarimjami]

Hi Dears
Hope fine and feeling well.
i have one question.
is it possible to get IP from both DHCP server and wireless router without confliction?

[Mukharjee]

Hi
I connected switch with router by using reverse patch card(reverse crimp cat5 cable). it is working fine. i can connect to another 8 systems in another building. Then connected from switch to wireless router with direct cat5 cable to normal port. With this I connected my laptop to internet in wireless mode. Hope this is useful.
Thanks
Mukharjee Pinapaka

[Natty1231]

I have a adsl modem connected to a wireless wifi router an wireless router connected to a switch. Everything is fine internet and network wise but for some reason I cannot connect FTP programs like mirc gigatribe etc even if I port foward on my modem and router. Can some one help please <email removed>

[umarwaqas789]

the router has no way of knowing that the IPs 192.168.1.7 and 192.168.1.8 addresses are already in use, and, as those IPs are within its DHCP scope