# Limitations of High Availability in Stateful Firewall Clusters

DevFeed: [Limitations of High Availability in Stateful Firewall Clusters](<https://devfeed.tech/articles/stateful-firewall-cluster-high-availability-theater-10978.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2024/04/firewall-ha-theater/>)

Published: 2024-04-10T05:59:00Z

Content type: opinion

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [Firewall](<https://devfeed.tech/topics/firewall.md>), [Availability](<https://devfeed.tech/topics/availability.md>), [BGP](<https://devfeed.tech/topics/bgp.md>), [networking](<https://devfeed.tech/topics/networking.md>)

Tags: [bgp](<https://devfeed.tech/tags/bgp.md>), [failover](<https://devfeed.tech/tags/failover.md>), [firewall](<https://devfeed.tech/tags/firewall.md>), [ha](<https://devfeed.tech/tags/ha.md>), [high-availability](<https://devfeed.tech/tags/high-availability.md>), [stateful](<https://devfeed.tech/tags/stateful.md>)

## AI overview

The article examines single-control-plane high-availability designs for stateful firewall clusters. It explains how synchronized sessions and forwarding state can preserve traffic through failover, while BGP Graceful Restart can keep peers forwarding as the new primary rebuilds its control plane. It argues that the shared control-plane design retains potential single points of failure and downtime.

## Source excerpt

Dmitry Perets wrote an excellent description of how typical firewall cluster solutions implement control-plane high availability, in particular, the routing protocol Graceful Restart feature (slightly edited): Most of the HA clustering solutions for stateful firewalls that I know implement a single-brain model, where the entire cluster is seen by the outside network as a single node. The node that is currently primary runs the control plane (hence, I call it single-brain). Sessions and the forwarding plane are synchronized between the nodes. Read more ...