The Dynamic Host Configuration Protocol (DHCP) Server is an essential component of the network and plays an important role in assigning the IP addresses, default gateways and other key network parameters. The app interface has a Servers tab giving access to common settings such as Network Interface, Start IP, Last IP, Lease Time, Gateway, Netmask, DNS Server Address and WPAD URL. There is also the ability to configure settings for WINS Server Address, TFTP Server Address and NTP Server Address. The Servers tab also lists unconfigured servers that are available on newly created interfaces.
The Lease Tab lists active IP leases and includes IP Address, MAC Address, Host Name and Lease Expiry as well as section to manage static leases.
The General Settings Tab gives access to Authoritative Mode and Maximum Leases settings.
The DHCP Server application is installed by default and can be accessed from the left-hand navigation panel.
To navigate to the DHCP Server app, Network Control -> Infrastructure -> DHCP Server Once you have navigated to the app, you will see a list of servers that have been configured and a list of available servers yet to be configured.
From this interface you can view an overview of each server including the assigned interface (physical, VLAN or Virtual), Gateway Address, Start IP, Last IP, default lease time and status of the server as well as edit the server parameters, enable or disable the server or delete the configuration for that server.
(Note: servers that have static leases set within their address range cannot be deleted until those static leases are removed from the server configuration.)
To edit a server, click the edit action on the corresponding line for that server and you should see the following interface.
From this Configure DHCP Server interface you can modify the following settings:
• Network Interface – This will be the network interface that this server will be associated with. The network interface can be a physical, virtual or VLAN interface that is present on the Crystal Eye Appliance.
• Start IP – This is the start of the IPv4 address pool assigned to this DHCP server.
• Last IP– This is the last IP of the IPv4 address pool assigned to this DHCP server.
• Lease Time – This is the duration of the lease that will be assigned to hosts that obtain an address from this server and can be expressed in minutes, hours, days, months and years. Default value is 7 days.
• Gateway – This is the IPv4 address of the gateway assigned to the hosts that obtain an address from this server. Default value is the IPv4 address of the interface assigned to this DHCP server.
• Netmask – This is the IPv4 network mask assigned to hosts that obtain an address from this server. Default value is the netmask assigned to the interface under Network Control -> Infrastructure -> Network Settings -> Netmask.
• DNS Server Addresses – This is a list of DNS server IPv4 addresses that will be assigned to hosts that obtain an address from this server. Default value is the IPv4 address of the interface assigned to this DHCP server.
NOTE : It is recommended to allow the Crystal Eye interface to be set as the DNS server to be able to perform DNS based traffic filtering in other applications.
• WINS Server Address – This is an optional field to specify the IPv4 address of a WINS server to allow legacy support of Windows Internet Name Service. By default, this field is blank.
• TFTP Server Address – This optional field is to specify the IPv4 address of a TFTP Server. TFTP Servers are typically set in environments where remote boot support is required. By default, this field is blank.
• NTP Server Address – This optional field is used to specify the IPv4 address of Network Time Protocol Server. By default, this field is blank.
• WPAD Url – This is the location of the Web Proxy Auto Discovery configuration file which allows the central configuration of Web Proxy settings on host devices connected to the network. By default, this is set to http://crystaleye.lan/wpad.dat.
The Leases tab allows access to the active leases assigned by the DHCP Server and controls to set up static leases.
The General Settings tab contains controls for enabling or disabling authoritative mode as well as setting the maximum number of sessions. In most cases, leaving this as the default is recommended except to cater for unique deployments.