Some advanced network settings can be found by navigating to Config | Network | Advanced. The Options tab has the following advanced configuration options:
Enable SIP NAT Helper: Most SIP solutions handle NAT on their own, but sometimes, rewriting of an address inside SIP by the NAT device is necessary. Enabling this will enable bypassed SIP sessions to be rewritten in the kernel. By default, this is off.
Send ICMP Redirects: ICMP redirects are used to alert machines if a shorter route to their destination is available. By default, this is on.
Enable STP (Spanning Tree) on bridges: If you want to connect your Untangle server to a switch via two cables for redundancy, you should check this option to ensure a loop-free topology.
DHCP Authoritative: If this is enabled, all DHCP serving is authoritative. By default, this is on.