Fujitsu ScanSnap N1800 Operator's Manual page 452

Another host or communication device is connected using the same IP
address as the scanner.
■ Action
If the same IP address has already been used by another host or communication device, then
even if the other device has been given a different IP address, the server may not recognize the
scanner's "duplicate" IP address until it is rebooted. Restart the server.
If a duplicate IP address connection from another host or communication device exists on a LAN,
it will be unusable.
If a duplicate IP address connection from another host or communication device exists, pull out
its LAN cable and restart the server.
Access is denied due to the establishment of a firewall between the
server and the scanner.
■ Action
If a firewall has been established between the server and the scanner, check that it has not been
set to deny access to the network.
The network Link Speed/Duplex Mode for the scanner and server are
different, or "Auto-Negotiation" is not supported by the server.
■ Action
For this scanner, the default [Link Speed/Duplex Mode] value is [Auto-Negotiation].
On the [Network Status] window, match the scanner and server's network Link Speed/Duplex
Mode settings. If the problem persists in spite of having set both the scanner and server's
network Link Speed/Duplex Mode settings to [Auto-Negotiation], select something other than
[Auto-Negotiation] and check again.
For more details about the [Network Status] window, refer to
Operating Status" (page
8.2 Network Connection Troubleshooting
121).
452
"4.8.7 Checking the Network