Why is Smoothwall not relaying DHCP addresses to my computers?

Article #: Product Castle

Software Unified Threat Management

Advanced Firewall



I have setup Smoothwall as a DHCP relay but the relay does not work. What could be wrong?


The configuration on the Smoothwall is according to the help but either:

  • The Smoothwall isn't relaying DHCP addresses out
  • The computers requesting DHCP addresses aren't receiving the IP addresses


  1. You should set the Smoothwall as the default gateway for the DHCP server, typically using an internal IP address to communicate on. Note that this IP address must be on a different subnet to the subnet used by DHCP requesting clients.
  2. Ensure the Smoothwall has a route to the networks it is relaying for.
  3. If the Smoothwall's internal IP address is not used for the DHCP server's default gateway, ensure the DHCP server has a route to the networks so it can act as a fallback for DHCP address requests.


Last updated: Author: Contributions by:
25 August 2016   Tanja