Last adaptation to the version: 14.1.1 (11.2025)
- New section Advanced settings when editing a pool
- 10.2026
- Overview of the DHCP leases now in the network topology
Prepare IP address ranges
UTMuser@firewall.name.fqdn Network
For the firewall to function as a DHCP server in a network, a fixed IP from the network range must be configured on the corresponding interface. In this example, IP addresses are assigned in network 192.168.222.0/24. To achieve this, an IP from this network is added to the interface. LAN3 → → IP addresses → In the selection box, enter or select the IP address from the desired network with the desired subnet mask, if applicable. Here 192.168.222.1/24
Set up DHCP server
General
| Caption | Value | Description | UTMuser@firewall.name.fqdn Network  DHCP-Pools
|
|---|---|---|---|
| Enable detailed logging: notempty New |
Off | When activated, all DHCP requests are recorded in the syslog | |
DHCP-Pools DHCP-Pools
| |||
| Ignore other SDHCP-Servers: | Off | When activated, other DHCP servers notempty are ignored
New: IPv4 and IPv6 | |
If more than 1000 IP addresses (across all pools together) are required via DHCP, the number of possible leases must be increased. This is done in the menu Area Extc Variables with the variable MAXLEASES. The value 0 corresponds to the default value of the service: 1000 leases. | |||
In the example, the following IP addresses are assigned
Pool start address:
Pool end address:
Either the IP of a public DNS server or the IP of the firewall itself can be entered here. In this example, the clients use the firewall itself as DNS.
Caution: Normally, the IP of the firewall is always entered here.
Edit pool
After the pool has been created correctly, the pool start and end address can be changed and other parameters of the DHCP pool can be set up to be passed to the DHCP client.
General
UTMuser@firewall.name.fqdn Network Network configuration
Changes to the pool range start and pool range end possible
Options - DHCP Optionen
| Option | Option number | Value | Description | UTMuser@firewall.name.fqdn Network Network configuration  Edit pool general area
|
|---|---|---|---|---|
| Router: | 3 | »192.168.222.1 | Router configured as in step 3 | |
| Domain name: | 15 | securepoint.local | Name of the domain in which the DHCP leases are assigned | |
| Domain name server: | 5 | »192.168.222.1 | Name server as configured in step 2 | |
| Netbios name server: | 44 | NetBIOS over TCP/IP Name Server Option | ||
| SMTP-Server: | 69 | Simple Mail Transport Protocol (SMTP) Server Option | ||
| NTP Server: | 41 | Servers should be listed in order of preference. | ||
| Vendor Encapsulated Options: | 43 | Values must be given coded. | ||
| TFTP Server Name: | 66 | profile.gigaset.net | The IPv4 address, or the hostname of the TFTP server option tftp-server-name text; | |
| Bootfile Name: | 67 | The name of the bootfile file option bootfile-name text; | ||
| Default URL: | 114 | https://teamwork.gigaset.com/gigawiki/display/GPPPO/DHCP+option+114 | Default URL option default-url string; | |
| VLAN ID: | 132 | The ID of the VLAN used option vlan-id code 132 = text; option vlan-id "128"; | ||
| Next Server: | The IPv4 address of the Next server | |||
| Default Lease Time: | 51 | 600 Seconds | Default validity period of the IP address if the client has not requested an explicit duration. | |
| Maximal Lease Time: | 7200 Seconds | Maximum validity period of the IP address in seconds that the client may receive when explicitly requested. | ||
| Reject unknown clients: | No | If activated Yes, an IP address is only assigned if there is a entry at Static DHCP tab for the MAC address of the client. notempty Changed standard behaviourab v12.7: The static lease entry for the DHCP must be in the same pool to be considered known. The static lease entry for the DHCP must be in the same pool to be considered known. | ||
notempty
New as of: 14.1.1 | |||
| |||
| Caption | Value | Description | UTMuser@firewall.name.fqdn Network Network configuration 
|
|---|---|---|---|
| ID | 5 | ||
| Name | Name Servers | ||
| Value | 192.168.222.1 | ||
Static DHCP
If hosts are to be assigned predefined IP addresses ( fixed IPs bound to the MAC address, but assigned by the UTM), these IPs can be reserved with static leases:
Configuration under Area Static DHCP button
| Host: | MaxMustermann-Laptop | Meaningful host name | UTMuser@firewall.name.fqdn Network Network configuration  Dialogue Add lease
|
| Ethernet: | 12:34:56:78:90:AB | MAC address of the host | |
| IP: | IP address to be reserved exclusively for this host | ||
| Save and close | Saves and accepts the lease and closes the creation dialogue. | ||
|
notempty
Important: Leases must necessarily be in an existing DHCP pool! |
UTMuser@firewall.name.fqdn Network  Static DHCP
| ||
|
notempty Joint use of static and dynamic IP addresses within a pool is possible. | |||
Static leases outside a pool
| Existing static leases that are not within a DHCP pool must be changed! If such leases are detected after an update, a message is displayed prompting to adjust the DHCP settings. It ist now possible that either
|
 Warning at login
| ||
Configuration of DHCP-Relay
With the DHCP relay, devices can receive their network configuration dynamically via the network, even if the DHCP server is located in another subnet.
- If there are multiple subnets on an interface and a DHCP relay is to be created for only one of these subnets, this is only possible via VLANs.
- For this purpose, VLANs are created for the subnets of the interface. One with all subnets that should have a DHCP relay and one with the remaining subnets.
- Then, the corresponding VLAN can be selected as the client-side interface instead of the entire interface.
- Subnet A with 192.168.1.0/24
- Subnet B with 192.168.2.0/24
- Subnet C with 192.168.3.0/24
Now a DHCP relay is to be defined for subnets A and C, but not for B. For this purpose, a VLAN LAN2.1 is created, to which subnets A and C are assigned. A VLAN LAN2.2 is also created for B. So there are:
- VLAN LAN2.1 with 192.168.1.0/24 and 192.168.3.0/24
- VLAN LAN2.2 with 192.168.2.0/24
With the DHCP relay, VLAN LAN2.1 is now selected as the client-side interface instead of LAN2
| Caption | Value | Description | UTMuser@firewall.name.fqdn Network  Network configuration DHCP relay overview
|
|---|---|---|---|
| activate Debug mode: notempty New as of v12.7.1 |
Off | ||
DHCP Relay IPv4 DHCP Relay IPv4 | |||
| DHCP server IP addresses: notempty updated Multiple entries possible |
»192.168.178.1 | IP addresses of the DHCP server/s The network/s in which the servers are located must be known to the UTM. | |
| DHCP-Relay Client Side Interfaces: | LAN2 | Interfaces for which the DHCP server is to be responsible. | |
DHCP Relay IPv6 DHCP Relay IPv6 | |||
| DHCP-Relay Server Side Interfaces: | LAN1 | Interface behind which a DHCP-v6 server is located. | |
| DHCP-Relay Client Side Interfaces: | LAN2 | Interfaces for which a DHCP-v6 server is to be responsible. | |
Overview of DHCP pools / leases
The menu provides an overview of assigned static leases and existing DHCP connections. Static leases can also be edited there directly.
Further information can be found in the wiki article on network topology.