Catching CARP: Overview of Firewall Failover Protocols
/ 1 min read
🔄 Understanding CARP and PFSYNC for Network Failover. The Common Address Redundancy Protocol (CARP), developed by OpenBSD, provides a free alternative for managing failover between firewalls by handling IP address handover. To ensure seamless transitions, CARP utilizes PFSYNC, which synchronizes connection states between primary and secondary firewalls. PFSYNC traffic, which is sensitive and substantial, is recommended to be transmitted over a dedicated network link to mitigate security risks. The latest version, PFSYNC 5, allows multiple message types per packet and includes detailed session state information. While tools like Wireshark do not decode PFSYNC, tcpdump can be used for analysis, providing insights into session states and IP addresses.
