Filters control access to and through the GTA Firewall. Outbound and Remote Access Filters are created in functions under the Filters section, while IP Pass Through Filters are created in the first IP Pass Through section. Most Automatic Filter options are not directly defined by the user. However, Inbound Tunnels can be configured using an Automatic Accept All filters option, and Stealth mode can be turned on or off in Filter Preferences.
Outbound, Remote Access and IP Pass Through Filters are defined using the same screen layout and process. Use the information on filter management and fields at the beginning of this section to create Outbound, Remote Access and IP Pass Through Filters.
¨ Note
Changes to filters will not be effective until the section is saved.
Outbound, Remote Access and IP Pass Through Filters use the same mechanisms for filter management, so this section is the same for all three kinds of filters.
A filter set is all the filters for a specific filter type. The order of the set is important. Each packet is compared to the appropriate set (Remote Access, Outbound or IP Pass Through) starting at filter one (Index 1) in the set. A comparison is performed sequentially against each filter until one of two events occurs:
A filter is matched. The packet is either Accepted or Denied based on the filter definition, and the actions associated with the filter are performed.
No filters are matched and the filter list is exhausted. In this case the packet is rejected.
Filters will be color-coded: for Accept, Green; Deny, Red; Enabled, Black on background color; or Disabled, White or Gray on background color.
Automatic filters are the filters generated by the firewall in the course of allowing events such as the arrival of expected response packets from DNS queries and mail servers.
Automatic filters can now be deactivated; this action will prevent the creation of filters required to use the firewall, so GTA recommends using this option for troubleshooting only.
Automatic Filters can now be logged, an option used for configuration testing. See Remote Logging for examples of Automatic Filter logs.
Once you have completed entering Network A collection of devices and connectors that create a physical communication connection between users, usually differentiated by being reached by using a common network address. A network is a group of devices linked by a common network addresses, either separate or part of an internet, and separate or part of THE Internet; i.e., ìThis officeís network is linked to three other networks to make up our company internet (physical structure). Our company internet carries the information exchanged and generated by people within our intranet, including those who can become part of our internet by a virtual (VPN) link. Our customers can reach us through an extranet that includes access to some information that is also available to our intranet, some of which is housed within our internet and some housed on servers accessed over the Internet (whole world internet). Our employees can access information over the Internet from the World Wide Web only if we authorize it.î See also: Protected, External and Private Service Networks Information, you can use the DEFAULT button to auto-configure an initial set of filters according to the defined configuration. Auto-configured filters will be left disabled or enabled according to their factory default (the most secure setting).
The Default command does not reset to original factory filters.
When a filter set is auto-configured, the filters do not retain manual changes. If you have custom filters you wish to save, either create new filters manually or print a copy of your configuration before auto-configuration to use in restoring custom filters.
Changes to filters will not be effective until the section is saved. If you leave the filter or filter set without saving, changes will be lost.
The Copy function can be used to copy the definition of one filter and apply it to a new blank filter. To copy a filter definition into the copy/paste buffer, click on the EDIT button of the filter you wish to copy. Once it is displayed, click the COPY button. Return to the filter list, insert a new filter in the desired location and click PASTE.
Combining multiple filters can be useful and efficient when they share similar criteria. This most often occurs when all the filter parameters are the same except for the destination port. Filters commonly combined are for SMTP, FTP, and HTTP, since these are all TCP-based protocols, and are often served from the same system.