Version 4.0 User's Guide

4. Configuring NetProxy Services

4.12. Firewall Settings

NetProxy contains a powerful rules-based firewall that allows you to specify which computers and services (if any) on your network can be accessed from the outside world, and which Internet hosts can be connected to from the machines on your network.

A typical firewall configuration will reject all incoming connections (incoming connections refers to connections into NetProxy, both from the Internet and from the computers on your own network) apart from connections from any of the machines on your NetProxy, and will allow outgoing connections to any destination. This is the default configuration generated by the configuration wizard, and it offers the maximum level of security.

Certain situations, such as setups where a world-visible SMTP or WWW server is running on a machine behind the firewall, may require changes to the default firewall settings in order to perform optimally.

Firewall rules in NetProxy are specified using standard slash notation. This allows you to easily add rules covering entire groups of hosts (subnets).

The firewall configuration dialog for adding and editing mapped ports appears below. More information on each setting is given below the picture and continues on the next page. To display specific help on each of the settings, click the Windows 'context help' icon at the top of the dialog box in NetProxy, then select the item you wish to learn more about.

Reject All Incoming Connections
Sets the default behaviour for connections into NetProxy to "reject". When this option is set, you then explicitly add one or more firewall rules to permit connections to NetProxy from the hosts on your own network.

Accept All Incoming Connections
Sets the default behaviour for connections into NetProxy to "accept". When this option is set, NetProxy will permit incoming connections from any hosts (both on the Internet and on your internal network) apart from those hosts excepted by any other firewall rules.

Incoming Connection Rules
Contains a list of firewall rules for connections into NetProxy. Hosts and subnets are specified using slash notation, and individual rules can be specified for each NetProxy service.

Add Incoming Firewall Rule
Adds a new firewall rule for governing which hosts can use the services of your NetProxy installation.

Edit Incoming Firewall Rule
Displays a dialog box permitting the currently selected incoming firewall rule to be altered.

Remove Incoming Firewall Rule
Removes the currently selected incoming firewall rule.

Block Outgoing Connections
Sets the default behaviour for connections out of NetProxy to "reject". One or more outgoing firewall rules must be added to cover the hosts that NetProxy is permitted to make connections to.

Accept Outgoing Connections
Sets the default behaviour for connections out of NetProxy to "accept". Any hosts that are covered by an outgoing firewall rule will not be reachable via NetProxy.

Outgoing Connection Rules
Contains a list of firewall rules for connections from NetProxy. Hosts and subnets are specified using slash notation, and individual rules can be specified for each NetProxy service.

Add Outgoing Firewall Rule
Adds a new firewall rule for governing which sites can be reachable via NetProxy.

Edit Outgoing Firewall Rule
Displays a dialog box permitting the currently selected outgoing firewall rule to be altered.

Remove Outgoing Firewall Rule
Removes the currently selected outgoing firewall rule.


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