Hands-on Junos CLI tutorials, OSPF and BGP configuration guides, SRX firewall policies and step-by-step network troubleshooting — lab-tested by working network engineers preparing for JNCIA, JNCIS and beyond.
Latest Guide
'Everything works until we enable screens, then traffic dies' is a classic SRX support thread. Flood and scan screens have real thresholds and real side effects — here is how to read the counters and tune the values instead of disabling protection.
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The tunnel was fine yesterday. Today it is down. Follow the Juniper KB approach: determine whether Phase 1 or Phase 2 failed, match proposals, proxy-IDs and PSKs, and use IKE traceoptions when nothing else explains it.
An SRX chassis cluster node goes disabled to prevent split brain, usually after the control link or fabric link fails. This guide shows how to read the Events reason, checks both links in order from cheapest to most expensive, ranks the root causes, and explains how to bring the node back safely.
Build an SRX site to site VPN as a route-based IKEv2 tunnel on st0, with a copy-ready Junos config, healthy and broken show output, and an ordered diagnostic. Includes the FortiGate and Palo Alto interop gotchas and the PFS mismatch that kills new tunnels at the first rekey.
SASE is SD-WAN plus cloud-delivered security (SSE), enforced at vendor PoPs instead of your headquarters firewall. This guide explains the architecture, maps the 2026 vendor field including HPE and Juniper, and shows how to tunnel an SRX branch into an SSE PoP with fail-open or fail-closed routing.
FortiGate suits most small offices without Junos skills, SRX suits Junos shops and routing-heavy branches, and Palo Alto suits security-first buyers. This comparison uses published datasheet numbers, explains which throughput row actually matters, and shows how to trial an SRX properly.
A Junos LACP ae interface that stays down is usually caused by the far end, not the Juniper box. Here is an ordered diagnostic, with root causes ranked by how often we see them, to get from Defaulted or Detached to Collecting distributing.
'Why can't I ping my management interface?' and 'the management interface cannot route' are standing r/Juniper questions. fxp0 on routers, me0 on EX, em0 on SRX — here is how the OOB interface really works and how to configure it right.
'My SRX345 is at 100% CPU' and 'EX switch high CPU' are constant Reddit and Juniper KB topics. Learn to identify rpd, snmpd, httpd and eventd as the culprit process and apply the right fix for each.
NMS dashboards full of 'SNMP timeout' on Juniper gear is a permanent support-checklist item. Juniper's own SNMP troubleshooting checklist covers the causes — polling method, bulk walks, large tables and firewall filtering. Here they are, in field order.