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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-655 => Topic started by: begs on February 10, 2010, 10:13:12 AM

Title: Strange problem with DHCP on DIR-655
Post by: begs on February 10, 2010, 10:13:12 AM
Here is the situation :  I configured the router (dir-655) to use 192.168.1.xxx DHCP range of addresses. Everything is fine when I connect to the router with a wire. When I connect to the WPA secured wireless with the passphrase, I receive this ip address : 192.168.0.100 and I have no access to internet. I tried to open the router page in a browser (http://192.168.0.1) and I get to the login page of a Dlink DIR-601 for which my admin password does not work.

When I manually enter a static IP address for my wireless adapter, in the specified range (lets say 192.168.1.20), I can access the right network (mine) and all is fine.

How can I obtain a wrong IP address from what seems to be another router when I choose the wireless network and input my own passphrase??? I am mystified. I did try to change the SSID to be sure it was not duplicated and all of the other networks in my range are secured in some way.

Any clue?

Thanks
Richard
Title: Re: Strange problem with DHCP on DIR-655
Post by: duffman on February 10, 2010, 12:45:21 PM
It almost sounds like your connecting to a different router wirelessly. Change the SSID to make sure it's your router your connecting too. Also make sure your not connecting to the guest Vlan.
Title: Re: Strange problem with DHCP on DIR-655
Post by: Sammydad1 on February 11, 2010, 03:43:20 PM
I agree...it sounds like you are picking up on a neighbors wireless signal.  It is entirely possible that you both have default SSID setings and routers from the same company..DLink...for example.

I would also suggets you change your SSID to something more easily identified for your needs, but not so easy that a nosy neighbor could see its yours....not that anybody ever has nosy neighbors.... 8-)


SD1
Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 12, 2010, 09:16:20 AM
I did change the SSID to something that is unique and still have the problem. It seems like a nonsense to me. All networks arount my building are secured so I should not be able to pick-up an address from them. I did a reset on the router and still the same. I wiped out all the info for my wireless adapter et refreshed the network list, chose mine, entered the password and still got this damn 192.168.0.100 which is wrong. Should I try to reinstall the firmware (seems like I have the most recent).

Thanks again for your help.
Title: Re: Strange problem with DHCP on DIR-655
Post by: kthaddock on February 12, 2010, 09:23:20 AM
Router Settings

Router IP Address: 192.168.?.?

Subnet Mask: 255.2555.255.0

Device Name:

Local Domain Name: (optional)

Enable DNS Relay: on/off

What DHCP settings can you read here ???

kthaddock
Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 12, 2010, 09:44:25 AM
Router IP address is : 192.168.1.1
Subnet is : 255.255.255.0
Device name : archer
Local domain : blank
Enable DNS relay : checked

I just noticed in DHCP client list of my router that there is a DIR-601 router connected to my network. Obviously, I pick my ip address from that router instead of mine (which I still don't understand). I could probably ask the owner of that router to change its subnet. How can I find out where that router is located??? There is 85 appartments connected to that network!

Richard

Title: Re: Strange problem with DHCP on DIR-655
Post by: Cobra on February 12, 2010, 10:16:06 AM
Router IP address is : 192.168.1.1
Subnet is : 255.255.255.0
Device name : archer
Local domain : blank
Enable DNS relay : checked

I just noticed in DHCP client list of my router that there is a DIR-601 router connected to my network. Obviously, I pick my ip address from that router instead of mine (which I still don't understand). I could probably ask the owner of that router to change its subnet. How can I find out where that router is located??? There is 85 appartments connected to that network!

Richard



If this is the info for your 655 then it appears you changed the IP address for the router.

Try logging into http://192.168.1.1
Title: Re: Strange problem with DHCP on DIR-655
Post by: Ronneske on February 12, 2010, 10:19:13 AM
can you check the neighborhood ssid's and explicitly try to connect to yours.
Maybe in the first attempt Windows has registered the 'not yours' router as the preferred one.

Unless you fix this preference it will connect to the stranger first !

Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 12, 2010, 10:41:57 AM
I have no problem connecting to MY router and access to the setup page (192.168.1.1) when I enter an IP address manually for my wireless adapter OR when I connect with a patch cord.

When I ask for an address through DHCP wirelessly, I get a wrong address (192.168.0.100) and the setup page I can reach (http://192.168.0.1) is a DIR-601 for which I don`t have the password. I tried many times to reconnect ti MY SSID and make sure it is unique and still the same. Now I have been able to determine that the wrong router is located on 5th or 6th floor of my building by physically unplug those floors from the network. Then, I get a good address. Does not explain WHY it is this router that provides me with the wrong address. I guess I will have to knock on all doors of those floor and ask to see their router setup...
Title: Re: Strange problem with DHCP on DIR-655
Post by: davevt31 on February 12, 2010, 10:44:05 AM
How are you connected to the Internet (Cable/DSL)? 
Did your provider give you a modem/wireless router combo and this is what your wireless is picking up?
Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 12, 2010, 11:08:46 AM
Connected through a dedicated DSL with a fixed address on a cisco router on which I have my DLINK wireless router connected.

It is also interesting to know that it has been working flawlessly for two years before I began to have this problem, this week.
Title: Re: Strange problem with DHCP on DIR-655
Post by: duffman on February 12, 2010, 11:38:38 AM
You're right about your neighbours device connected to your router and effectively running two dhcp servers which are giving out ip's. But if your network is secured how is this rogue hardware connecting to your router? Seems to me something in your wireless security isn't quit working right. Are you using WPA2?
Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 12, 2010, 01:26:47 PM
My security is WPA2. I managed to find the appartment where my problem was. His router is connected with a patch cord to the network. That is why his DHCP was available to the network. I did change his range of address from 192.168.0.1 to 192.168.100.1.

I still do not understand how it could interfere with my 192.168.1.1 range but it did solve my problem. If any of you guys (thanks for your help) think of a reason, let share it...

Bye
Title: Re: Strange problem with DHCP on DIR-655
Post by: duffman on February 12, 2010, 02:12:02 PM
So it was all connected by wires? Why is your neighbours ethernet plugged into your router?
Title: Re: Strange problem with DHCP on DIR-655
Post by: begs on February 14, 2010, 05:20:45 AM
I manage the building. It is a retirement residence and we provide internet in the appartments through a local lan. People are free to use their own devices on the lan and they often don't advise me before.
Title: Re: Strange problem with DHCP on DIR-655
Post by: duffman on February 14, 2010, 01:46:05 PM
I'm not so sure providing a local lan is that secure. If one resident has a rogue infected computer it could spread like wild fire. Plus unencrypted traffic is exposed. Do these residents know that you could monitor all their traffic. I know you probably don't but they should know that it is a possibility.
Title: Re: Strange problem with DHCP on DIR-655
Post by: dwong604 on July 26, 2010, 09:48:38 AM
Hi, i registered an account so i can post on this forum.  I'm having the exact same problem as the OP. 
Here is a little background:

I live in a town house complex, there's about 30 other units in my area and some apartment buildings within range.  My cable provider is Shaw and I have a dedicated modem in my suite.  From the modem i have my DIR-655 connected.  All wired computers are fine.  Once in awhile, my wireless computers will be picking up a different subnet.  By default i'm on 192.168.10.x however sometimes i'm getting 192.168.100.x
I've changed the SSID on my wireless, flashed to the newest firmware and i've also done a factory reset on the router, still the same issue. 
When i get the wrong IP address, i'm able to bring up the gateway's logon page through IE, however i don't have the password for the page. 

Any suggestions?
Title: Re: Strange problem with DHCP on DIR-655
Post by: kthaddock on July 26, 2010, 11:43:11 AM
If you picking different subnet then it's your ISP-problem to solve. You getting IP ip from your ISP.
Title: Re: Strange problem with DHCP on DIR-655
Post by: EddieZ on July 26, 2010, 03:12:47 PM
No way the router changes subnet on its own. ISP determines your IP.
Title: Re: Strange problem with DHCP on DIR-655
Post by: dwong604 on July 27, 2010, 10:00:04 AM
Thanks for the reply guys, i'm pretty sure i'm not getting an IP from an ISP. First off, all wired computers are working, so that means that my router is handling DHCP properly.  With my wireless devices, i'm connected through a specific SSID.  (My ssid is actually all digits, everybody else that is broadcasting their SSID, all letters, there are one or two that are alphanumeric, but none are all numeric. 
Its a hit and miss with my situation and i'm noticing it more on my two apple computers then my windows 7 laptop.  It shows that i'm connected to the right IP address, but when i logon to the gateway its a different "gateway" name. 
Title: Re: Strange problem with DHCP on DIR-655
Post by: lurobi on July 31, 2010, 02:42:14 PM
I have the same problem If I attempt to change the router's IP to 192.168.0.1.  When I changed the IP, The DHCP settings changed as well.  But clients kept getting assigned IP addresses of 192.168.0.x, even though the router displayed them as having 192.168.1.y (x and y were not the same).

I wasn't able to solve this, and had to change the router's IP back to 192.168.0.1.

This problem only affected my wired connections, and persisted through reboots and resets.

EDIT: Nope, I had a second DHCP server handing out IPs on my network.  Not the router's problem.
Title: Re: Strange problem with DHCP on DIR-655
Post by: EddieZ on August 01, 2010, 02:58:53 AM
Check for double DHCP on the LAN.

Also, there is a difference between the DIR gui LAN IP and the DHCP range IP. Also (double DHCP) the modem or device supplying the WAN address also plays a role. So you need to mention here what your setup is: dynamic, static etc.
Title: Re: Strange problem with DHCP on DIR-655
Post by: lurobi on August 02, 2010, 07:07:12 PM
Check for double DHCP on the LAN.

After you said that it occurred to me that months ago I had run a dhcp server for the 192.168.0.0 subnet on one of my computers.  Sure enough it was still up and probably competing with the dlink to assign IPs.
Title: Re: Strange problem with DHCP on DIR-655
Post by: RickNCN on March 24, 2011, 08:51:11 AM
Yeah, pretty weird this problem, until you see the simple reason for it:

Somewhere on your LAN there is a device with a DHCP server running.

Simple test: disconnect all other ethernet wires from your wifi router and try again. Problem disappears.

 So it happens like this: once you authenticate on your wireless network, you are also on your LAN. There is then another device, either another router or another server or PC connected to it with a DHCP server running. You would *think* your wifi router would "get to" your pc first and assign the DHCP lease, but maybe it was busy with other traffic for a millisecond and the other DHCP server responded to the broadcast packet for DHCP. So it assigns the address it knows which may or may not be different than your own router.

The most common reason is someone is using a router as a switch. They are plugging a cable from your router into a LAN port on their router to "share" it with a few more PCs. This will work, but the downside is that DHCP is usually enabled on the LAN ports of a router by default so it messes up all other PCs on that network. What that person *should* do is connect your network wire into their WAN port. That way, you act as their "Internet Provider" and their network is private from your network and your LAN never "sees" their DHCP server.