Modem resetting when client joins AP

  vinnyo123 21:39 23 Jul 2005

Let me start with topology

Modem>Router with 4 port switch>wireless AP.

Router giving IP to AP clients (DHCP). Other clients static Ip.

I have noticed on occasion that my modem will loose connection resulting in router to lose IP(WAN). Most of the time it will reinitialize by it self and sometimes I would have to disconnect from power and let it initialize to get IP from ISP.

I narrowed it down to my wife's laptop from work. Every time she boots up it would reset my modem (cable BB).

So far I came up with her laptop sending out UDP packets on ports 137,138 and 139 (netBIOS ETC.)every minute. Also UDP on ports 1032.1031 and 1210 and maybe some I missed.

Now I understand that 137,138 and 139 is usual but every minute throws up flags and other ports sends flags for spyware and ad ware.

My question is: I am looking for other possibilities to look into. I cannot run any software for ad ware or spy ware do to her company policy. I have spoke to her company support and they advised me not to touch her laptop. So as I wait for her techs to run scans I am looking for something I may have overlooked.

Her laptop is WIN XP,VPN and firewall RSA SecurID also using Lotus Notes and a Web database. I am currently looking into maybe all this software is sending out a broadcast on initial boot and knocking modem offline.

Any advice or more info needed?

As always thanks in advance.

  Forum Editor 23:05 23 Jul 2005

if your wife's laptop is knocking the modem offline. My own laptop runs quite happily on all kinds of different setups, both private and corporate, and although I work constantly with wireless and wired networks I've never experienced a problem.

My daughter's work laptop is configured in precisely the same way as your wife's, and she can use my wireless network without any problems at all. My guess would be that there's a modem-related problem - which model are you using?

  Forum Editor 23:08 23 Jul 2005

you say "other clients static IP"

What exactly do you mean by that - what other clients? Are you saying that some machines are wired on this network?

  vinnyo123 23:15 23 Jul 2005

I am using linksys befcmu10.

I understand what you are saying I never ran into this before but I tested her laptop on boot many times and every time her laptop boots it is making the modem lose it's connection and other PCs on the network show loss of connection.

This is a weird one ; to confirm on boot I loss link/act lite on modem and other PCs show loss of connection and after her laptop finishes starting up modem re initializes (most of the time).

The only thing I came up with so far is listed above if anyone has some suggestions to troubleshoot much appreciated.

  vinnyo123 23:26 23 Jul 2005

Ok I am using static IPs on three wired PCs(routers switched ports). Also I am using DHCP through router to give out IP's & etc. to PCs that jump on my AP. wife's laptop and my laptop.

DHCP is configured to give out IPs in the range of 192.168.100 to 105. Statics are under 50. ex .18, .5, .10.

My other laptop is not causing this problem.
I just thought of this maybe router is having problems giving out IPs through AP(wap54g)

thanks again for your responses.

  mgmcc 08:54 24 Jul 2005

Is it possible that there is an IP address conflict due to the cable modem itself having an IP address in the range?

My Telewest Cable Modem's IP address is

  vinnyo123 11:48 24 Jul 2005

Modem and Router are separate units not combined.
I am positive that there are no conflicts of IP's.(there listed above). It only happens when that particular Laptop boots up.

  vinnyo123 13:09 25 Jul 2005

Sorry to all for keeping this open; but it's a tricky one. I confirmed it is wife's laptop, next day I tested it on boot up and of course it resets modem and I loss connection.

I am going to wait for her jobs tech. support to scan and give me suggestions. Don't think I'll get to much help from them because it's not interfering with her laptop and there network.

I would run more test after they finish and give me no answers. I would keep this post open and get back in a few days. I need a solution as I am running a live server on LAN and really can't afford to the loss of internet connection.

Thanks again for any suggestions.

  vinnyo123 15:17 25 Jul 2005

FE if you don't mind.

I am trying another approach I noticed that every time my wife jumps on another AP point she has to manually change her IE>connection>LAN settings>advanced settings.

One of her jobs software keeps changing setting to automatically detect settings or to use proxy not sure which one right now(don't have access to laptop) but it is definitely one or the other.
Because of this her jobs support suggest she unticks this and she is able to connect.

I am thinking maybe this is the cause. Can you check if the laptop you where referring to has the same setting on boot.

Thanks again;
PS I just cannot give up LOL

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