Linksys BEFSR41 & IBM Wireless Gateway

[LPang]

Hello,

I've been using a Linksys BEFSR41 for the last year successfully on my broadband cable net access at home. Recently, I purchased an IBM ThinkPad T30 that came with built-in wireless wifi. IBM also threw in an IBM High Rate Wireless LAN Gateway. This gateway is also a router, hardware firewall, NAT, 4 port wired 10/100, and 802.11b.

I've decided to keep the Linksys router with my desktop computer connected to it. I've attached the IBM gateway to the Linksys (Standard port, not the uplink, doesn't provide the IBM with access for some reason). My ThinkPad is wirelessly connected to the IBM gateway. Everything appears to work just fine. The Linksys router provides DCHP to the desktop and the IBM gateway. The IBM gateway in turn provides DCHP to my wireless notebook. Everyone and everything can get on the Internet just fine.

However, the problem I have is that neither computer can see each other. So I can't share directories, files, or printers. The only way I can do those things is if I wire my Thinkpad directly into the Linksys router.

I know I could probably just use the IBM gateway and sell the Linksys, but I've found the Linksys to have better support in terms of hardware firewall and ease of port triggering. Is there a way to make the IBM gateway behave like it's just an extension of the Linksys router?

Help would be greatly appreciated. I can provide additional details if the situation still isn't clear.

Thank you.

 

[bcastner]

On one of the routers you need to disable DHCP services and its gateway role.

I am certain you can do this in Linksys, but I do not know anything about the IBM product.

What is happening is that you have created a new subnet with the IBM router, and the machines on different subnets cannot see each other.

So, one one of the routers:

1. Assign an IP address in the fixed range (non-DHCP) of the DHCP-enabled router;
2. Turn off DHCP in this router;
3. Turn off "Gateway" services and enable just router functionality.

Your cabling is fine.

 

[LPang]

Hi,

Thanks for the tips. I think I understand the situation now that you've mentioned that the IBM router has created a new subnet.

[Cable Modem] -> [Linksys] -> [IBM]

According to your information, I can assign a fixed IP to the IBM outside of the DHCP range of the Linksys. Kill the DHCP abilities on the IBM.

However, I've gone through the setup pages for the IBM. It appears that I can turn off the DHCP abilities in the IBM. I can't turn off Gateway services. Unless there is another term for it that I'm missing.

I have noticed that both the Linksys and IBM support something called Static Routing. I've looked it up in both manuals but I still don't quite understand how to manipulate it. I believe that it might allow me to make the IBM a part of the Linksys? Is that about right?

The IBM's details can be found here:

http://www-3.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-4ZDQAK

Thanks for your help everyone.

 

[bcastner]

You do not have to do any static routing.

Tell the IBM on one of its first screens that it is using a fixed ip address.

Advanced Configuration:
DHCP Disable
IP address 192.168.1.2 (or whatever static IP from the non-DHCP pool of the Linksys) Subnet 255.255.255.0
Set up your wireless configuration: SSID, etc.
Save Changes. Restart the IBM.

Take a cable from any regular LAN port of the Linksys and stick it into the WAN port of the router. Let the Linksys handle DHCP, PPoE or whatever to your ISP.

The client on the IBM when they reboot should receive a DHCP assigned IP from the Linksys, be on the same subnet as all Linksys connected users, and have access to the internet and LAN side clients.

 

[LPang]

I attempted to set the IBM to Fixed IP:
IP: 192.168.1.200
SubMask: 255.255.255.0
Gateway: (tried 192.168.1.1 which is the Linksys. It also doesn't like being set to 0.0.0.0 or the Gateway that the ISP assigns to the Linksys)

The general error I keep getting is that the LAN IP address can't be in the same subnet with the Internet-broadband IP address. I'm assuming that it's detecting that the IP being set as Fixed is the same as what itself is.

This is what my system summary on the IBM looks like at the moment:
LAN Status
IP Address : 192.168.1.101
Subnet Mask : 255.255.255.0
DHCP : Disable
DHCP Start Address : 0.0.0.0
DHCP End Address : 0.0.0.0

Internet-Broadband Status
IP Address : 192.168.1.101
Subnet Mask : 255.255.255.0
Gateway : 192.168.1.1
DNS Server 1 : 24.153.22.195
DNS Server 2 : 24.153.23.66

When I get the Thinkpad to connect either wirelessly, or via cable, nothing happens since it can't get an IP address. I've set all the wireless items and restarted the IBM. As you've recommended, I've taken a cable from a regular por ton the Linksys and stuck into the WAN port of the IBM.

 

[bcastner]

You are almost there. By the way, it looks like a very capable router if the feature set of the setup screens are any indication.

The Linksys by default has an IP of 192.168.1.1, by default it assigns through DHCP addresses in the range 192.169.1.100 -- 192.168.1.150.

So, for your downstream router to work we need to give it a fixed IP that is not in the Linksys DHCP range (note: this is different than the IBM router).

In the configuration of the IBM router, you want to:
specify a fixed address, (not dynamic or PPoE)
disable DHCP
Under Advanced Configuration, Lan Configuration set an address such as 192.168.1.2, subnet 255.255.255.0.
It might complain, but ignore the complaint).

You are done. This is essentially the advice given in the "Troubleshooting" section of the manual, other than IBM keeps thinking that the address must be in the DHCP range of the upstream router. This is not true for Linksys.

The gateway for all devices should be 192.168.1.1, which is the Linksys. This will be true for your wireless clients as well. When a wired or wireless client connects it broadcasts a request for DHCP services. The Linksys will answer and provide the dynamic address.

One last thing you might want to do if it is not in use somewhere else is to go to the setup page of the Linksys, Advanced, DMZ and put the fixed IP of the downstream IBM router in the Linksys DMZ zone. (in this example, 192.168.1.2).

 

[LPang]

So I set the fixed IP of the IBM router to 192.168.1.300, and it should be out of the Linksys DHCP range. Will the IBM permit the gateway to be set to 192.168.1.1? By setting the DMZ to the IBM on the Linksys, that might actually take care of that problem, but I'm not sure.

Kill the DHCP on the IBM as well, and set the LAN Config to 192.168.1.2 with a subnet of 255.255.255.0.

The IBM does look like a pretty good unit. It lists for around $299 CDN apparently, but IBM was giving them away with high end ThinkPads in December. I was planning on just using the IBM for everything and putting the Linksys aside; except I don't know if the IBM has as good firewall protection. Not to mention, the Virtual Server (Port forwarding?) doesn't appear to work at all or I have no idea how to make it work. I've followed the instructions in the manual but I couldn't get the router to forward 3389, 80, or 21. Oh well. It's all a learning experience.

I'll try it out tonight and let you know. Thanks for all the help.

 

[fs483]

LesterPang,

Unfortunately the last octet of the IP address must be below 255 ! 192.168.1.300 IS NOT A VALID.

Bootleg