Linksys BEFW11S4 with WAP54G

[SteveM11]

I hope someone can help. I am having trouble configuring a new access point I added to my already wired/wireless network. I had set up a BEFW11S4 which is a wireless router with 4 port switch. Connected to the switch I had 3 computers and an additional 16 port switch for the additional computers. 1 level of our firehouse had poor service so I added an accesspoint (WAP54G) to the wall and ran the ethernet cable to the switch. Now I have 2 places computers can wirelessly connect to the internet (old router which is upstairs, and new accesspoint downstairs). Is is possible I have the same SSID on both? I am frequently having a problem one one of the hard wired computers saying their are 2 computers with similar IPs on the system. Very confused and unsure why this isn't working smoothly. Linksys is really no help although they usually are. Any help is appreciated. Thanks in advance!

[spiderbite]

Basically, from what I can gather, you have a situation where you have a wired network that has an ip range in the same range as the DHCP the Linksys is using.

I need to know how many wired computers you have and what the ip address range is. I am assuming from your problem that these have static IP addresses.

Assuming you haven't done anything to the linksys, they should be a 192.168.x.x.

I think your problem is that some if not all of these computers have a static IP, meaning they have been configured with an IP that does not change.


The linksys is giving out dynamic addresses most likely are in the same range as the static addresses. What is happening is the Linksys doesn't know about the static IP's and therefore gives out an address that is currently in use.

Find out what the addresses are on all the wired computers and then post them so we can tell you where to start your dynamic range so they can be on the same "network" without interfering with the static range. You want to start your dynamic range (DHCP) slightly above the last static address, so the Linksys never gives out one of those addresses.

My father and brother are both firefighters so getting to help a "brother" is a big treat.

What part of the world are y'all in?

[SteveM11]

Ok, I think i understand. We have a printer used for dispatching with a static IP, 192.168.1.90. Everything else is dynamic (I believe) 192.168.1.100 and up.... we are on long island in NY, I really appreciate your help, im really not sure why im having such a problem, thanks!

[spiderbite]

well, the only thing I can think of now is that both of the linksys wireless units are starting at 192.168.1.100.

You need to check this out first and see if this is the case. If so, one of the units should be changed so it doesn't interfere with the other.


Without boring you to death and assuming you haven't changed much on the linksys you should have a subnet mask that says 255.255.255.0

To normal people this means you have 254 addresses you can use.

since you are starting at .100 and up the lower numbers aren't in use except for the linksys boxes which might be 192.168.1.1

Actually, if you haven't changed anything they both might be 192.168.1.1

I need you to check the linksys boxes and find out the IP addresses on them. You need to change one of them if they are both the same. The only number you are allowed to change is the very last .1 to a .2 or something.

this is the last octet, which we dont have time for here. but your "network" is 192.168.1.x, the "x" being the variable that changes from .1 to .255.

Now, the .1, suggests the "gateway". there will only be one. the .255 suggests the "broadcast" which you cant use and now is not the time to ask why.



My fear is that you have two linksys boxes that use 192.168.1.1 as the address for the unit itself. You need to change one of them to .2. I also suspect that the DHCP range on both boxes starts at .100


You need to assess the number of computers you have and want to use on the network.


Most likely, the DHCP ranges on the linksys units are from 192.168.1.100 to 192.168.1.254.

I would split this up and make one of them 192.168.1.2 to 192.168.1.80 and leave the other one alone. you couls split it up anyway you want as long as you only change the last octet.

This way you have done the following:

192.168.1.1 is the address on one of the boxes
192.168.1.2 is the address on the other.

One DHCP range set to 192.168.1.2 - 192.168.1.80 for addresses for computers.

(This leaves 192.168.1.81 - 99 for static addresses if you need it which is where the printer is at 192.168.1.90)

The next range is left alone at 192.168.1.100 -254.

I think that will work.

The DHCP range can be set in the Linksys box under the DHCP tab.


The very first thing you should do is find out what address is being duplicated and go from there.

There is a private message system on this board, send me your phone number and I'll call you and walk you through it. I'll be awake....

[SteveM11]

I am not on location now but i should be able to do what you said. I know my router is 192.168.1.1 and my AP is 192.168.1.245. You have a good point and now I realize what is happening. I didn't realize the AP had a DHCP server, but I will check into the config menu when I am at our building. Do you know if it is possible to make the SSID the same as the router so It looks like 1 larger wireless network and not 2 different access points??? Again, thanks for all your help.

[spiderbite]

That is exactly what you want to do. With disparaging SSID's you will not be able to roam from one location to the other nor will the upstairs people work downstairs etc...

The AP is giving clients addresses to associate with....hope this helps...

[spiderbite]

you could turn dhcp off on the AP and that should fix everything....

[SteveM11]

Im not sure how to do that. I looked on linksys website and it said the AP doesn't have a DHCP server.... Is that possible?

[M/Q]

Hope it is OK to jump and help a bit. The best test right now would be to go on each computer and get to a command prompt. Then type ipconfig /all. Look at what the DHCP server's IP addr is. It should be the same on all of the computers, if you explained the network topology correctly. I wanted to check that as well. You have an Internet perimeter device, aka DSL modem or such. Does that plug into the WAN/Internet port of the router? If so then the router should be the only active DHCP server. The access point does not have the ability to act as a DHCP server if my memory serves me right. Don't laugh Spider. Do you have the access point setup to accept its IP addr info automatically or use a static IP addr?

The critical juncture right now is to see what the results of the ipconfig test is as that will explain a great deal. Also as Spider so aptly stated if you need devices with static IP addr's please make sure that they are outside the range of the DHCP server but within the range of the subnet.

I also have to mention as having been a volunteer firefighter for 10 years that I am proud to welcome you to the forum.

[SteveM11]

All systems returned a DHCP server of 192.168.1.1 weather they are connected to wireless router via Cable/Wireless and even the AP i have on the lower level. Any ideas?

[SteveM11]

well i noticed im not having that problem at all since ive changed the ssid of the AP to match that of the router and put them on the same channel and set the AP to "b" mode only (router is B only), now everything is working fine..... pretty strange

[M/Q]

Are there any other wireless networks in the vicinity? An short association with a different network might have created a DHCP lease that was long enough and in the same subnet to cause the problem. If that happens again, I might suggest moving off of the default subnet. It is a good idea to do that anyway.

[spiderbite]

M/Q,

Thanks bud, for the help. I think where I confused myself was the AP having a static address as opposed to getting one from the router thing.

This is why I'm the ladder monkey and not the network admin. Hey, but I'm working on it.

By matching the ssids.. did that not converge two identical subnets into one?

[M/Q]

Hey Spider, quit picking on yourself. I am almost clueless when it comes to Cisco, and that is where you shine. I am just a networking guy that started a really long time ago.

[SteveM11]

I am close to a network nextdoor and it had the same ssid as my access point when i was having issues. All working fine since ssid was changed to match router...

[M/Q]

I thought so, that was the problem. You should change your IP addressing then as well, so that will not happen again. I suspect you are on the same frequency as well, so you may want to change the channel as well, and make sure to get as far away from the other channel as possible.

[SteveM11]

That makes sense now, I can't believe I didn't figure that out in the first place. Thanks again for the help.

Steve