Using The New Bridges of FreeBSD 15

Hacker News

February 22, 2026

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FreeBSD 15 introduces a significant upgrade to its bridging implementation, offering native support for VLANs and enhanced performance. The new system streamlines network configuration by allowing a single bridge to handle multiple VLANs, tagged or untagged, on each member interface. This eliminates the need for creating separate bridges for individual VLANs, which was cumbersome in older versions. The update also deprecates the ability to assign layer 3 addresses on member interfaces, aligning FreeBSD's behavior more closely with that of a hardware switch. A key feature is the `vlanfilter` flag, which enables tagged VLAN support and prevents errors when adding members without it. Prior to this release, network setups involving multiple VLANs required intricate configurations. Users often faced challenges managing bridges for each VLAN, leading to complex rc.conf files and increased administrative overhead. The new bridging design simplifies this process, allowing administrators to specify VLANs directly on the bridge with a single command. For instance, configuring a bridge to handle tagged VLANs 2, 3, and 128 now requires just one line in `rc.conf`, making network administration far more efficient. The performance improvements are notable, particularly for high-speed networks. The old system saw degraded packet processing as the number of member interfaces increased, which was problematic for setups aiming to achieve line rate speeds (e.g., 10Gbit). FreeBSD 15's optimized packet handling addresses these limitations, ensuring smoother operation even with multiple VLANs and network devices. For developers and administrators working with VNET jails, the new implementation removes reliance on external scripts like `jib` for creating stable epair(4) devices. The kernel now natively generates MAC addresses based on jail host IDs, simplifying jail configuration and ensuring consistent device naming. This

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Originally published on Hacker News on 2/22/2026