| Chapter 12. System Services | ||
|---|---|---|
 |  | |
| Chapter 12. System Services | ||
|---|---|---|
| | | |
Table of Contents
A system service provides general functionality, and runs as a separate concurrent process alongside normal traffic handling.
Table 12.1 lists the services that the FB6000 can provide :-
Table 12.1. List of system services
| Service | Function |
| SNMP server | provides clients with access to management information using the Simple Network Management Protocol |
| NTP client | automatically synchronises the FB6000's clock with an NTP time server (usually using an Internet public NTP server) |
| Telnet server | provides an administration command-line interface accessed over a network connection |
| HTTP server | serves the web user-interface files to a user's browser on a client machine |
| DNS | relays DNS requests from either the FB6000 itself, or client machines to one or more DNS resolvers |
Services are configured under the "Setup" category, under the heading "General system services", where there is a single services object (XML element : <services>).
The services object doesn't have any attributes itself, all configuration is done via child objects, one per service. If a service object is not present, the service is
disabled. Clicking on the Edit link next to the services object will take you to the list of child objects. Where a service object is not present, the table in that
section will contain an "Add" link. A maximum of one instance of each service object type can be present.
Whilst the FB6000 does have a comprehensive firewall, the design of the FB6000 is that it should be able to protect itself sensibly without the need for a separate firewall. You can, of course, configure the firewall settings to control access to system services as well, if you want.
Each service has specific access control settings, and these default to not allowing external access (i.e. traffic not from locally Ethernet connected devices). You can also lock down access to a specific routing table, and restrict the source IP addresses from which connections are accepted.
In the case of the web interface, you can also define trusted IP addresses which are given priority access to the login page even if there is a denial of service attack against the web interface.
Normally connections that aren't accepted are rejected, however there is a setting tcp-stealth in the global system settings which can be used to ignore them instead.
This is useful to conceal from potential attackers that there is something capable of responding to TCP at the FireBrick's address.
| | | |
| 11.3. Ether tunnelling |  | 12.2. Common settings |