Synopsis # This chapter provides deterministic troubleshooting playbooks for common production faults: High Availability (HA) role flaps, asymmetric paths at multi-WAN edges, tunnel MTU black holes, IPv6 Neighbor Discovery (ND) and Router Advertisement (RA) problems, and practical Quality-of-Service (QoS) verification. Each playbook uses base tools only: packet filter policy in pf.conf(5) inspected with pfctl(8) , interfaces via ifconfig(8) , live captures with tcpdump(8) , system controls wi...
