I use sonic wall VPN to work form home. I use a lan BUT I also have a Belkin Wirelss N. When I plug into the wireless I cannot log into the VPN BUT everyone can use their laptops. Is there a way to work this so we can all use the internet and I don't have to unplug and rework everything just to work from home?

Check the Advanced tab of the N300's Firewall settings to see if VPN passthrough is enabled. If it's not, the firewall will cut off VPN communications.

You may also need to run the VPN Wizard on the N300.

Here's the manual:
http://cache-www.belkin.com/support/dl/F9K1004v1%20manual%20-%20revA00.pdf

What the method of Using WIFI on my Simens Gigaset SX682 Wimax

are you running the Cisco VPN client from home, where this Belkin is your gateway and connecting to say your work?
If so, have a look in the settings of the Belkin to see if you can enable VPN Pass-through.

Try disabling some of the firewall functions on the belkin to isolate the issue and turn the rest back on.

If for some reason this model doesn't work even after the above, try changing the VPN client's connection settings,there are only two to choose from... (click modify on your connection entry, go to the Transport tab > then choose from:
IPSec over TCP and IPSec over UDP (port 10000)

The UDP flood suggests a possible DoS (Denial of Service) attack which hoses your connectivity but doesn't harm your PC or change anything. Can you surf the web through the Belkin okay when not VPN ing? Is it just your VPN connection that doesn't work? Do you get any message or dialog boxes popping up when you try to connect saying anything about the remote host not reachable or you username/password is not valid. You VPN client should be giving you some indication of the failure to connect. Any other PC at home to VPN to work with? Also possible that your PC has been denied access to work because your PC caused problems on the corp network. You probably would not be aware of that. Is there an IT department at work to support you?

You really don't need the cd to install the router - if you connect the router to your PC with an ethernet RJ45 cable, this should give you access to your LAN & the internet. You can then access your router to set up your wireless connectivity.

To access your router open your web browser & in the address bar, type 192.168.2.1 - you might be asked for a username & password - for username: admin password: leave blank or if this does not work type : admin for password

this is not so much a soloution but an idea!
from memory the netopia devices allow you to configure a dmz device by IP or MAC address.

I have had to do something similar but with a buffalo unit instead of your linksys. I ended up having to place the buffalo unitin into a dmz created on the netopia unit. before VPN tunnles were formed correctly.

please tell me that who is your ISP at home?

My guess is that dhcp is using the same private network scheme. Try changing your home network scheme to something different than your office.
For example:
Office = 192.168.1.x
home = 192.168.2.x

the router is not configured by default as an access point.
to use the phone the router must be configured as an access point, which is more than disabling security, nat and dhcp must be removed..
page 53 of the user manual describes the proceedure.
online the manual is here
http://belkin.httpsvc.vitalstreamcdn.com/belkin_vitalstream_com/support/dl/p75170-d_f5d8231-4_man.pdf

well, first of all the i also have the N1 belkin wireless modem router, in order for it to connect, there has to be a wireless connection in your area for you to connect to, if any of your neighbors so have wireless you can connect to their network, but if you are not getting a conection that means no one around you has wireless or lan, the belkin wireless is not a internet provider it just extends the distance of your internal wireless. some networks may be secured as well, sometimes you can only connect to unsecured networks unless you have the name and passcode for the secured network.