The Services Menu¶
In this page you find:
The 4i Edge X includes many useful services to prevent threats and to configure the networks and the running daemons, whose activation and set up is explained in this section. Among them there are the DHCP server for internal zones, the intrusion detection system, and the Serial Port service. The available services appear as items in the sub-menu list on the left-hand side of the screen.
DHCP server–DHCP server for automatic IP assignment
Time server–enable and configure the NTP time server, set the time zone, or update the time manually
Intrusion Prevention System–configuration of the IPS snort
SNMP Server–enable or disable support for the Simple Network Management Protocol
Quality of Service–IP traffic prioritisation
Serial port–configure the serial port
Docker–run your container on 4i Edge X
DHCP server¶
The DHCP server is used by the clients (both workstations and servers) in the zones controlled by the 4i Edge X to receive an IP address (called lease), either dynamic or a fixed lease, and communicate with other local and remote devices.
The DHCP server configuration consists of three pages, namely Server configuration, Fixed leases, and Dynamic leases.
Server configuration¶
The DHCP server on an 4i Edge X can be enabled on each active zone independently. For each of the zones enabled on the 4i Edge X, this page show one checkbox, hence at least the Enable DHCP server on GREEN interface option appears. There are corresponding checkboxes for the ORANGE and BLUE zone if they are activated.
At the bottom of the page, there is a textfield, labelled
Custom configuration lines, that can be used by advanced
users to write custom configuration lines to be added to the
dhcpd.conf file (e.g., custom routes to subnets), like
this example shows.
Warning
The custom configuration lines must adhere to the syntax
of the /etc/dhcpd.conf file–check the manual page
dhcpd.conf (5) or see it online at
https://linux.die.net/man/5/dhcpd.conf, since they are not checked
for errors and are inserted verbatim in the configuration
file. Any typo or mistake might prevent the DHCP server from
starting correctly!
To customise the DHCP parameter for each zone, tick the respective checkbox. A panel labelled Settings will appear: click on it to show the available options.
Settings
- Start address, End address
The range of IP addresses to be supplied to the clients. These addresses have to be within the subnet that has been assigned to the corresponding zone. If these two fields are left blank, the whole IP range of the zone will be used to assign dynamic leases.
Hint
If some hosts should receive a fixed lease, (see below), make sure their IP addresses are included neither in this range nor in the range of the OpenVPN address pool (see ) to avoid conflicts.
- Allow only fixed leases
Tick this checkbox to use fixed leases only. No dynamic lease will be assigned.
- Default lease time, Max lease time
The default and the maximum time in minutes before the assignment of each lease expires and the client requests a new lease from the DHCP server.
- Domain name suffix
The default domain name suffix that is passed to the clients and that will be used for local domain searches.
- Default Gateway
The default gateway that the clients in the zone will used. If left blank, the default gateway is the 4i Edge X itself.
- Primary DNS, Secondary DNS
The DNS used by the clients. Since the 4i Edge X contains a caching DNS server, the default value is the firewall’s own IP address in the respective zone, though a second server or even the primary value can be changed.
- Primary NTP server, Secondary NTP server
The NTP servers used by the clients, to keep the clocks synchronised. Leave blank to use the 4i Edge X's default NTP server.
- Primary WINS server, Secondary WINS server
The WINS servers used by the clients. This option is only needed for the Microsoft Windows networks that use WINS.
Once done, click on the button at the bottom of the page, then on the Apply button in the green callout that will appear to restart the DHCPD server with the new configuration.
Fixed leases¶
It is sometimes necessary or desirable for certain devices to always use the same IP address while still using DHCP, for example servers that provide a service (like, e.g., a VPN server or a code repository) or devices like printers or scanners.
A fixed lease is also called Static IP Address, since a device will always receive the same IP address when requesting a lease from the DHCP server.
This page contains the list of all the fixed leases defined in the local networks, providing several information about that lease: The device’s MAC Address and the assigned IP address, a remark, and the available actions.
By clicking on the button, a static IP address can be assigned to a device. The devices are identified by their MAC addresses.
Note
Assigning a fixed lease from the DHCP server is very different from setting up the IP address manually on a (client) device. Indeed, in the latter case, the device will still contact the DHCP server to receive its address and to announce its presence on the network. When the IP address required by the device has already been assigned, however, a dynamic lease will be given to the device.
The following parameters can be set for fixed leases:
- MAC address
The client’s MAC address.
- IP address
The IP address that will always be assigned to the client.
- Remark
An optional description of the device receiving the lease.
Advanced options
In this panel appear three additional options.
- Next address
The address of the TFTP server. This and the next two options are useful only in a few cases (see below for an example).
- Filename
The boot image file name. Option needed only for thin clients or network boot.
- Root path
The path of the boot image file.
- Enabled
If this checkbox is not ticked, the fixed lease will be stored but not written down to the file
dhcpd.conf.
A use case for a fixed lease.
A use case that shows the usefulness of a fixed lease is the case of thin clients or disk-less workstations on the network that use PXE, i.e., boot the operating system from an image supplied by a networked tftp server. If the tftp server is hosted on the same server with the DHCP, the thin client receives both the lease and the image from the same server. More often, however, the tftp server is hosted on another server on the network, hence the client must be redirected to this server by the DHCP server, an operation that can be done easily adding a fixed lease on the DHCP server for the thin client, adding a next-address and the filename of the image to boot.
Note
All leases assigned by the DHCP server are stored by default
in the /var/lib/dhcp/dhcpd.leases file. Although the DHCP
daemon takes care of cleaning that file, it may happen that the
file stores leases that have already been expired and are quite
old. This is not a problem and does not interfere with the normal
DHCP server working. A typical entry in that file is:
lease 192.168.58.157 {
starts 2 2019/06/11 13:00:21;
ends 5 2019/06/14 01:00:21;
binding state active;
next binding state free;
hardware ethernet 00:14:22:b1:09:9b;
}
Dynamic leases¶
After the DHCP server has been activated, and at least one client has
received a (dynamic) IP address, the table in this page will feature
the list of the clients, with these additional information: assigned
dynamic IP addresses, the MAC address of the connecting device and its
hostname, the expiry date and time, and the status, which can be
either expired or active.
Time server¶
The 4i Edge X uses NTP to keep its system time synchronised with time servers on the Internet. There is only one settings, displayed in the Network time server panel.
Network time server
A number of time server hosts on the Internet are preconfigured and used by the system, along with the time zone. Available options are the following.
- Override default NTP servers
Tick the checkbox to replace the default NTP servers. This might prove necessary when running a setup that does not allow the 4i Edge X to reach the Internet. Several time servers addresses can be supplied, one per line, in the small form that will show up; each of them will be written in the configuration file, as value of the
serveroption. For better performance, at least two time server should be provided here.Hint
Each custom time server can be written as a hostname or IP address. Entries can be also vendor-specific, like e.g.,
0.endian.pool.ntp.org.
Note
If for some reasons the 4i Edge X's clock is not synchronised anymore with the NTP servers and the difference between them is high, there is the chance that a manual synchronisation be necessary. This can be done either by clicking on the button, or in the Localization options, under the System Settings (), by manually entering the correct time and date.
Intrusion Prevention System¶
The 4i Edge X includes the well known Intrusion Detection (IDS) and Prevention (IPS) system snort, which works directly in close contact with into iptables, to intercept and drop connections–if required–from unwanted or distrusted sources.
Settings¶
If snort is not active, a grey switch appears on the page and can be clicked on to start the service. After a short interval, the page will contain some options to configure the service.
Intrusion Prevention System settings
This panel allows to define the automatic download and installation of the snort rules.
- Automatically fetch SNORT Rules
Ticking this box will let the 4i Edge X automatically download the snort rules from the Endian Network.
Note
If the 4i Edge X is not registered, or its maintenance has expired, rules are not downloaded anymore. An informative message is also shown at the bottom of the page.
- SNORT rules update schedule
The frequency of download of the rules: A drop-down menu allows to choose one of the Hourly, Daily, Weekly, or Monthly options. This option appears only if the previous option has been activated.
- Rules last updated
An informative message about the last time rules have been manually downloaded, like for example:
2019-08-01 10:48:31By clicking on this button, the signatures for the IPS service will be immediately downloaded from the emeringthreats.net web site.
Pick one file from the file selection window that opens upon clicking this button.
Click on this button to upload the file and use it with snort.
Rules¶
The list of rulesets that are stored on the 4i Edge X appears in this page, along with the number of rules they contain and the actions that can be done on them.
It is possible to edit each ruleset independently, by clicking on the icon in the rightmost column, Actions, but when at least one ruleset is selected, atop the table a few buttons will appear, allowing to carry out bulk actions on all the selected rulesets at once. On the right-hand side of the button, a number in a green circle shows how many rulesets are currently selected: Click on it to select all (including those in other pages) or none of the datasets.
The rule policies in snort.
By default, the policy for all the rulesets is set to
alert, shown by the 
icon. This means that
whenever a flow of traffic will match the corresponding rule or
ruleset, the traffic will be allowed to pass and the intrusion
attempt will be logged.
This behaviour can be changed by clicking on the alert icon to
toggle the policy into block, shown by the icon
, with the result that the intrusion attempt will be
blocked, but no message will be recorded in the log files.
After a policy of a rule or of a whole ruleset has been changed, it is necessary to click on the Apply button, for the changes to be applied.
After clicking on the Edit button, the list of the rules included in the selected ruleset(s) is shown, which can be narrowed down by entering some terms in the text box next to the Search label. To go back to the previous page, click on the Back to rules link on the top left corner of the table.
Warning
Turning on the IPS only implies that snort is running, but not that it is already used to filter the traffic. Indeed, the IPS is used only on those firewall rules, defined in the various Firewall configuration pages, that are configured with the Allow with IPS Filter policy .
SNMP Server¶
The SNMP is used to monitor network-attached devices, and can be used e.g., to control the status of the internal infrastructure.
To enable the SNMP Server is sufficient to click on the grey switch. Once done so, a few options will appear in the Settings panel.
Settings
- Community String
A key that is needed to read the data with an SNMP client.
- Location
An identification string that can be set to anything, but it is suggested that it describe the location of the 4i Edge X.
- Override global notification email address
The SNMP Server requires to configure an e-mail address as the system contact, and the global e-mail address provided during the installation procedure is used by default. In order to use a custom e-mail address, tick the checkbox to activate the next option.
- System contact email address
Write the e-mail address of the administrator to be contacted.
Quality of Service¶
The purpose of the QoS module is to prioritise the IP traffic that is flowing through the 4i Edge X depending on the service. In other words, the QoS is a convenient way to reserve a given amount of the available bandwidth (both incoming and outgoing) for a given service. Applications that typically need to be prioritised over bulk traffic are interactive services such as SSH or VoIP.
Tagging¶
The fourth page is different from the others as it is used to classify and prioritise traffic. In other words, the traffic can be marked or tagged to allow external devices to handle it accordingly. This is particularly useful in a scenario with limited bandwidth and the uplink device, e.g., a modem, can only prioritise traffic based on TOS or DSCP flags in the packets. When clicking on the link the editor opens, which is similar to the one under the Rules page. These are the available options:
Source
- Type
Choose from the drop-down menu the traffic source, either a Zone or interface, a network or an IP, or a MAC address. Depending on this choice, different values can be specified: A zone or interface from the available ones from those that will be displayed, or one or more IP addresses, networks, or MAC addresses. The default value is
<ANY>, meaning the rule will be applied to all traffic.
Destination
- Type
Choose from the drop-down menu the traffic destination, either a Zone or interface, a network or an IP. Depending on this choice, different values can be specified: A zone or interface from the available ones from those that will be displayed, or one or more IP addresses or networks.
Service/Port
- Service
The service that the rule should match.
Hint
User defined permits to specify a custom protocol and the ports to block, an option that proves useful when running services on ports different from the standard ones.
- Protocol
The type of traffic that is interested by the rule: TCP, UDP, TCP+UDP, ESP, GRE, and ICMP. TCP and UDP are the most used, GRE is used by tunnels, ESP by IPsec, and ICMP by the ping and traceroute commands.
- Destination port
The destination port for the rule.
Note
There exist dozens predefined services that can be chosen from the drop-down menus and should suffice to cover the most use cases. An user defined combination of port and protocol should be used only if a service is not running on a standard port (e.g., the SSH server listens to port 2345 or the web server runs on port 7981) or if a service, not included in the list, is using a particular port.
TOS/DSCP
- Type
Choose from the drop-down menu which tag to use to mark the traffic: a TOS flag, a DSCP class or a DSCP value. Depending on the choice, one of the following three options will appear.
- Tag traffic with the following TOS flag
This dropdown appears only when TOS is chosen in the Type option above. It allows to define the TOS flag that will be set in all matching packets.
- Tag traffic with the following DSCP class
This dropdown appears when choosing DSCP Class in the Type option above. It allows to define the DSCP class that will be set in all matching packets.
- Tag traffic with the following DSCP value
This field appears only when DSCP value is chosen in the Type option above. It allows to enter a custom value for DSCP, that will be set in all matching packets.
- Enabled
Tick the checkbox to enable the rule.
- Comment
A comment to identify the rule.
Serial Port¶
The Serial Port pages allow to configure the 4i Edge X‘s serial port as either serial console or serial server in three different operational modalities: Server, client, or console. The configuration options are grouped into two pages, Port configuration and Serial server.
Port Configuration¶
In this page it is possible to configure the available serial ports on
the 4i Edge X, by clicking on the corresponding 
icon.
Change serial port configuration
The available options are:
- Remark
A comment about the serial port’s configuration.
- Enabled
Tick the checkbox to enable the serial port.
- Enable console
By ticking the checkbox, it will be possible to connect to the 4i Edge X via the serial console.
Hint
The Serial Server page allows no configuration if this option is enabled.
- Serial Port standard
Choose the type of the serial port from the drop-down menu. Available options are: RS-232, RS-485, and RS-422.
- Baudrate
The speed in baud of the serial port. Available values can be selected from the drop-down menu.
Hint
Modern appliances use a speed of 115,200 baud.
- Parity
Choose the parity of the communication from the drop-down menu among the available values: None, Even, and Odd.
- Data bits
Select the data bits from the drop-down menu. Available values are 5, 6, 7 and 8.
- Stop bits
The stop bits value, either 1 or 2, chosen from the drop-down menu.
Advanced settings
When the standard used is rs232, an additional option can be configured in this panel.
- Flow control
Choose the type of control to be applied to the traffic flow. Possible values are none, ctsrts, and xonxoff.
Serial Server¶
This page carries only an empty table if in Port Configuration the Enable console option has been ticked; no configuration is allowed. The table shows the configuration–initially displaying only the name of the serial port–of the serial server.
- Enabled
Tick the checkbox to enable the serial port.
- Remark
A comment about the configuration.
- Operation mode
Choose from the drop-down menu one of the available operation modes: Raw Client and Raw Server.
- Server IP
This option only appears when Raw Client is selected. Supply one IP address to which to forward the traffic when connecting to the serial port.
- Server Port
This option only appears when Raw Client is selected. Supply one port to which the traffic through the serial port will be directed.
- TCP Port
This option only appears when Raw Server is selected. Provide a TCP port that will allow serial connection.
Advanced settings
- Enable debug mode
By ticking this checkbox more information about connections through serial console will be logged: This proves useful for e.g., troubleshooting.