What is the minimum number of network connections in a multihomed firewall?

A multihomed firewall configuration typically involves separating different network segments for enhanced security. A common secure setup includes at least three connections: one for the external network (Internet), one for the internal trusted network, and one for a Demilitarized Zone (DMZ) where public-facing servers reside, thus requiring a minimum of three interfaces.

Five connections are possible for more complex setups but not the minimum required for a basic multihomed configuration that includes a DMZ.

Four connections are also possible, for instance, if there are multiple internal zones, but three is considered the practical minimum for a standard secure multihomed firewall.

Two connections represent a simple dual-homed firewall, but the term 'multihomed' in a security context often implies more granular segmentation beyond just two zones, commonly including a DMZ.