Junos SRX Security Policies in Real Life: Why Traffic Doesn't Match
Debug SRX policy issues when traffic flows wrong or NAT fails. Covers zone chain, policy hit counters, flow trace, and the top 5 reasons policies never match.
#troubleshooting
8 posts tagged with "troubleshooting"
Policy Routing Debug: Why Traffic Takes the Wrong Path
Debug policy-based routing on VyOS. Covers rule evaluation order, mark verification, table inspection, common misconfigurations, and why PBR debugging needs systematic verification.
ARP and Neighbor Discovery: Troubleshooting Layer 2 Problems
Debug ARP and IPv6 ND issues on VyOS. Covers ARP table analysis, stale entries, duplicate IP detection, proxy ARP, neighbor discovery, and why Layer 2 problems look like Layer 3 failures.
Packet Capture on VyOS: tcpdump Techniques for Real Debugging
Master packet capture on VyOS for troubleshooting. Covers tcpdump filters, capture strategies, decoding protocols, saving and analyzing captures, and why packets never lie.
Conntrack Deep Dive: Connection Tables, Limits, and Debugging
Master VyOS connection tracking internals. Covers conntrack tables, tuning limits, timeout configuration, debugging full tables, and why conntrack is the invisible stateful firewall engine.
TCP MSS Clamping: When and Why to Adjust Segment Size
Master TCP MSS clamping on VyOS for tunnels and PPPoE. Covers MSS vs MTU, clamping configuration, troubleshooting fragmentation, and why MSS clamping fixes problems MTU changes cannot.
MTR, Tracepath, and PMTUD: Diagnosing Path Problems
Master network path diagnostics on VyOS. Covers MTR interpretation, traceroute variants, PMTUD troubleshooting, detecting packet loss patterns, and why ping alone is never enough.
QoS on VyOS: Making Latency Feel Better
Practical traffic shaping and QoS configuration on VyOS. Covers queue disciplines, traffic prioritization, fighting bufferbloat, and understanding where the actual bottleneck is.