This article applies to the Smoothwall Filter & Firewall On-Prem solution in either Hardware or VM form.
A Primer on DHCP.
The UTM version of the Smoothwall Filter & Firewall Appliance or Software comes with a built-in DHCP server and DHCP Relay function, so that IP allocation for connected clients can be made directly from the Smoothwall itself, or requests can be relayed across LAN interfaces to a remote DHCP Server.
The DCHP Server and Relay currently support 20 interfaces, which includes Basic, Bridged, Bonded and VLAN interfaces. As with most DHCP servers, the Smoothwall implementation allows for the creation of multiple concurrent DHCP servers, servicing individual networks, with IP reservations available based on a MAC address, or reservations applied to existing clients from the ARP table. Addresses are pulled from a single, or multiple dynamic pools, which are user defined. The Smoothwall DHCP implementation also supports custom DHCP options, should your use-case require them.
Acting as a relay, the Smoothwall will listen for any DHCP requests made on the defined interfaces and relay those requests to the user-defined primary and secondary DHCP servers, facilitating DHCP allocation from a remote server across the LAN.
Configuring DHCP Servers.
- Log-in to your Smoothwall Filter & Firewall Admin UI.
- Navigate to Services > DHCP > Global. Enable the DHCP service in Server mode, optionally enable logging, and check any interfaces you wish to provide DHCP services on.
- Navigate to Services > DHCP > DHCP Server.
- Under DHCP Subnets, select an 'empty' profile and give it an appropriate name.
- Under Settings, configure the parameters of the DHCP allocations. There are more options under the Advanced button. Be sure to enable the configuration. If specific DHCP options are required, they can be configured under Services > DHCP > Custom Options.
- At the bottom of the page, click Save.
- Under 'Add a new dynamic range' add a start IP and end IP for the range of addresses to pull from and click 'Add dynamic range'. Restart the DHCP as prompted.
- Repeat for all interfaces that require DHCP services.
Configuring DHCP Relay.
- Log-in to your Smoothwall Filter & Firewall Admin UI.
- Navigate to Services > DHCP > Global. Enable the DHCP service in Relay mode, optionally enable logging, and check any interfaces you wish to provide DHCP Relay services on.
- Navigate to Services > DHCP > DHCP relay. Configure a primary and secondary DHCP server as required and save.
Troubleshooting DHCP.
With logging enabled, any configuration error that may prevent the DHCP server from running will be logged under Reports > Logs > System under the DHCP Server heading.
If a newly configured interface is not present in the DHCP Global page, contact Smoothwall Support.