Weird connectivity issue

woo

For the last 4 days at 4:30 my browsers (firefox & ie) / messenger have suddenly stopped working on my laptop. I can still use the VPN client to work if it is running, but not open a new connection. I can ping websites if i have the ip address and can also ping other machines on my network.

The desktop will continue to run with no issue, the only way to get the laptop to see the net again is to reboot.

All machines run through a netgear router so not sure why it is only affecting one out of 3 machines.

Spyware scans and anti-virus scan return empty.

Anyone got any ideas?

amosworks

Can you ping domain names or is that where it falls over?

I guess you're using Windows, so if it is that then go to the command prompt and type "nslookup" and see what it says. Copy it here.

albertross_2

Is this wireless, not someone else coming home and switching their router on and causing wireless interference?

Does a repair work (right click on wireless icon)?

What do you mean by "but not open a new connection"? Is this a vpn only issue, have you adjusted the mtu to take account of the extra packet size? Are you using the cisco client?

woo

don't think it is interferance as it doesn't affect the other wirless pc's.

Todays example might explain it better..

PC 1 and Laptop 1 were sat next to each other.
Both connected wirelessly to the same router (Netgear MIMO)

both used from 7:30 this morning, running browsers, mail clients and VPN Client (portwise / citrix)

at 4:30 laptop 1 drops it's connection to the outside world for browsing and mail. openiing up a command prompt i can ping https://www.google.com, but wont open in a browser. repairing doesn't work, neither does switching the wireless connection on the laptop off and back on. reboot and it works fine.

pc1 had no issues at all and carried on happily.

laptop 2 used on and off during the day, also connecting wirelessly doesn't suffer any issues.

make the problem any clearer?

DrBenway

Any time schedules on the router/firewall set to 4.30

Any scheduled tasks on the PC.

It is unusual to see that you can ping google but not http. Doesn't messenger use http aswell. I seem to remember blocking a http url to stop messenger working at the office some years ago. Suggest a firewall is stopping it or is faulty. Or something is hijacking your http requests.

Are other tcp packets/ports ok ? http, ftp etc...

Might need to do some network snooping. Try nmap/ethereal ?

albertross_2

Was the laptop using a vpn and work proxy server all day? If so, did you try browsing after disconnecting from the vpn, and unticking the proxy in IE?

DrBenway

Good point albertross.

also if you set up a standard win xp vpn connection and make no changes to the network settings all traffic gets routed through the gateway on the remote network (vpn properties/networking/tcpip/advanced). I uncheck this so your routing table is only updated with the new pptp connection and not allowing it to update your default gateway. Then write a route script to add any routes manually. I can then get 2 vpns up simultaneously (so long as on different sub nets ) and continue to use the web locally rather than through the restrictions of the remote gateway.

woo

nothing scheduled on router or pc - only schedule on router is to turn the pretty lights off so it doesn't annoy other half

if it does it again tomorrow, watch it not now, i'll get ethereal and nmap on it.