Connecting one particular laptop to the wireless connection disrupts internet access

[DammyDani]

Hello, I'm Dammy. Theres a problem i've been battling with for the past few days and i was hoping someone could help me out. Whenever i connect a particular acer laptop to the internet at work via the wireless, internet access is lost after a period that ranges from 30 minutes to 1 hour and i have to reboot the VSAT modem to restore internet connectivity. This cycle of rebooting the vsat modem to restore internet access goes on and on until the problematic laptop is powered off.

Initially i thought the problem was with the modem since i always had to restart it, but i noticed that if i didnt take that laptop to work, internet access stayed up the whole day.

The acer laptop is enabled for DHCP and connects to a cisco wireless acess point that is connected to a cisco 2960 series switch which is in turn connected to the VSAT modem.

Looking forward to your reply.
Thanks a mil

[mjdodd]

do you get the same problem if you connect using hard wire ethernet. If so then it is in the laptop in terms of its taking over the modem.
since you say that without the connection the modem works it would seem to me that the wireless connection may be overheating the modem (it has to trasmit and receive and this can involve dispersing heat in th output transistor the transmitter pat of it. If this is the case then you may need to look at cooling the modem in some form.
A very rare but none the less real possibility is that here are other wireless signals (eg fro a close by microwave) that are interrupting your signal and then the modem then hangs.
M

[DammyDani]

Thanks for your reply mjdodd. Yeah, i get the same problem when connected via ethernet. Also, the problem occurs whether that laptop (my laptop actually) is using DHCP or static addressing. I guess my laptop is taking over the modem in a way, but i cant figure out how.

[mjdodd]

I suspect the laptop is starting ok with the modem and then perhaps the output on the electronics (ethernet and Wireless) are getting 'jammed' and thus locking the modem into waiting for the signal from the output side of the laptop which has seized. if reinstalling all the drivers (ethernet and wireless and perhaps the modem) does not work then I fear it may be professional electronics help.
Increasingly it sounds to me like a heat buildup problem and then an electrical component switching off to prevent damage.
m

[sknake]

It sounds like this laptop isn't being a good citizen on the network. It could be malicious software or a misconfiguration on the laptop.

Download Wireshark and install it on the problematic ACER laptop. Start a packet capture, connect it to the internet at work, let it remain online for some time, stop the packet capture then post it here. Once we take a look at the pcap we should have a pretty good idea of whats going on.

DISCLAIMER -- Password and other sensitive information may be contained in the packet capture. Normally I try to keep everything on the forum but due to the sensitive nature if you want an FTP to upload the file then let me know.

[DammyDani]

Thanks a lot guys, i think i've been able to solve the problem. I cleaned the acer laptop of viruses, trojans etc. with Kaspersky internet security and i also enabled DHCP snooping on the switch. The network has been fine for the past three days, with or without the acer laptop connected to the network.

Thanks a mil

[sknake]

Please mark this thread as solved (as you solved your own problem :)) and good luck!