D-Link DFL-260E User Manual page 118

3.4.5. ARP Advanced Settings
Summary
ARP Query No Sender
Handles ARP queries that have a sender IP of 0.0.0.0. Such sender IPs are never valid in responses,
but network units that have not yet learned of their IP address sometimes ask ARP questions with an
"unspecified" sender IP.
Default: DropLog
ARP Sender IP
Determines if the IP sender address must comply with the rules in the Access section.
Default: Validate
Unsolicited ARP Replies
Determines how NetDefendOS will handle ARP replies that it has not asked for. According to the
ARP specification, the recipient should accept these. However, because this can facilitate hijacking
of local connections, it is not normally allowed.
Default: DropLog
ARP Requests
Determines if NetDefendOS will automatically add the data in ARP requests to its ARP table. The
ARP specification states that this should be done, but as this procedure can facilitate hijacking of
local connections, it is not normally allowed. Even if ARPRequests is set to "Drop", meaning that
the packet is discarded without being stored, NetDefendOS will, provided that other rules approve
the request, reply to it.
Default: Drop
ARP Changes
Determines how NetDefendOS will deal with situations where a received ARP reply or ARP request
would alter an existing item in the ARP table. Allowing this to take place may facilitate hijacking of
local connections. However, not allowing this may cause problems if, for example, a network
adapter is replaced, as NetDefendOS will not accept the new address until the previous ARP table
entry has timed out.
Default: AcceptLog
Static ARP Changes
Determines how NetDefendOS will handle situations where a received ARP reply or ARP request
would alter a static item in the ARP table. Of course, this is never allowed to happen. However, this
setting does allow the administrator to specify whether or not such situations are to be logged.
Default: DropLog
Log ARP Resolve Failure
This determines whether NetDefendOS will log failed ARP resolve requests or not. Logging can be
used for monitoring purposes and can be helpful for troubleshooting network related problems.
However, disabling logging can prevent attempts to "spam" log receivers with failed resolve
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Chapter 3. Fundamentals