In order to discover drive.web devices or to change a device's IP address, savvy sends a local multicast message to port 48556 and the device responds with a unicast message.

This means that firewalls should be set to allow UDP traffic on port 48556.

All driveweb devices are shipped with their IP address set to This address was chosen because it is unlikely to conflict with existing IP addresses.

WindowsXP SP2 Problem

The firewall that is part of WindowsXP SP2 discards all multicast responses that come from outside the local subnet. This means that if your computer is not on the same subnet at and the WindowsXP SP2 firewall is turned on, you will not be able to communicate with your new drive.web devices.

This problem was corrected in Windows Vista and probably does not affect other firewalls. i.e. as long as port 48556 is open for UDP, firewalls other than the one built into WindowsXP SP2 will work.

WindowsXP SP2 Workarounds

  1. Turn off the WindowsXP SP2 firewall. This is not always possible, due to security considerations, but it is often a reasonable solution for networks that are not connected to the outside world.
  2. Add a second IP address to the network adapter. This second address should be set so that is on the local subnet (e.g.
  3. Use a different firewall.

Port 48556 is registered with the Internet Assigned Number Authority) as com-bardac-dw.