Dialup and Wifi at same time

  • Thread starter Thread starter Chris Hagwood
  • Start date Start date
C

Chris Hagwood

We have mobile users on a dial-up connection via CDPD. I would like
them to be able to get to the network via WiFi cards when the drive up
to hotspots.

How do I get the mobile apps to use the dial-up, while allowing other
apps to use the WiFi when they are in range?
 
If 'the mobile apps' use fixed servers in your backend, you can add a static
route to your server IP range for the CDPD adapter
(on each laptop)

Depending on the Windows version you use client side, Windows will be smart
enough to route over WiFi when available, and dial-up otherwise

What's the problem with having the mobile apps use WiFi?
 
Jeroen van Bemmel said:
If 'the mobile apps' use fixed servers in your backend, you can add a static
route to your server IP range for the CDPD adapter
(on each laptop)

Depending on the Windows version you use client side, Windows will be smart
enough to route over WiFi when available, and dial-up otherwise

What's the problem with having the mobile apps use WiFi?
Click to expand...

The backend servers for the mobile apps validate and let the users in
through the firewall based on their static IP's. So, that traffic has
to go through the CDPD network.

When they're in a wifi hotspot, I want everything else to go through
the wifi.

Is there an easy way to tell it the two or three IP servers to use
CDPD exclusively, and then try WiFi for everything else first? They
are on WinXPpro.
 
Use 'route add <server ip> mask 255.255.255.255 <gateway ip> -p'

Either once for each server, or for a range of IP addresses

You can add 'if <number>' to force it to use a specific adapter, else
Windows will find one for you
The -p is to make the route permanent, i.e. reboot won't destroy it
You may need a boot script in case there are multiple gateways (if these
clients are managed by some domain controller, you can probably come up with
some group policy that does that. I'm no expert on that though)

JvB
 
Jeroen van Bemmel said:
Use 'route add <server ip> mask 255.255.255.255 <gateway ip> -p'

Either once for each server, or for a range of IP addresses

You can add 'if <number>' to force it to use a specific adapter, else
Windows will find one for you
The -p is to make the route permanent, i.e. reboot won't destroy it
You may need a boot script in case there are multiple gateways (if these
clients are managed by some domain controller, you can probably come up with
some group policy that does that. I'm no expert on that though)
Click to expand...


Thanks Jeroen for your help so far, here is where I'm at now:

It seems that the computers in the field function exactly the opposite
as I had expected. When they are connected to the dial-up connection,
they send all network traffic through that connection. Even if it
fails, it doesn't seem to try to send it through the WiFi. If I add a
route using your instructions, that works.

Is there a network setting somewhere that I can change to tell it to
try the WiFi first, then try dial-up? (except for the servers I spoke
about previously)
 
Hi Chris,

The behavior you describe is windows' default behavior. You can override
this in several ways, but a detailed discussion will take many lines

When the dial-up connection is made, the default route appears to be
modified to point to this adapter.
http://www.microsoft.com/technet/community/columns/cableguy/cg0903.mspx says
that in theory the fastest network adapter should be elected (WiFi?), but
that does not seem to happen in your case

One thing you might try, is to set
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\<GUID>\DontAddDefaultGateway
for the dial-up connection. However, this may result in the dial-up not
being used at all...

The 'Dead gateway detection' mechanism (see above link) may help you for TCP
applications. You may need to tweak it (timing etc). However I have no
experience with this.

Another option would be a connection manager type of application to be
installed on each laptop

Regards,

Jeroen
 
Back
Top