IP Address Blocking dialog
(Main window -> Tools menu -> IP Address Blocking)
Someone sending an extreme number of DNS requests in rapid succession may be a hacker trying to crash the server or prevent others from using the service.
You can use the functions in this dialog to automatically or manually block such hackers or IP addresses which for any reason run amok sending you DNS requests.
Please note that this feature does not block traffic other than DNS requests - to block any other type traffic use a firewall.
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Auto block
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Automatically block IP addresses which send to many DNS requests too quickly
Use to enable/disable automatic blocking
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Maximum DNS requests per second
When an IP address sends more than this number of DNS requests in one second, it will be automatically be blocked (a "Blocked" rule will be added to list below) and further requests from this IP address are ignored.
A typical workstation computer should not send more than 10-25 requests in one second, but we recommend you set this value to at least 30 so that no legitimate clients get blocked.
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Block
Specify for how long automatic blocks should last (when/if the automatically added "Blocked" rule should expire).
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IP Address Blocking Rules
List of current blocking rules.
Use the "Add" / "Edit" buttons to enter rule details in the IP Address Blocking Rule dialog, and use the "Remove" button to remove a rule.
There are two types of rules; "Blocked" and "Trusted".
DNS requests from "Blocked" IP addresses will simply be ignored.
"Trusted" IP addresses will not be blocked automatically even if they exceed the "Maximum DNS requests per second" setting above.
