Step-by-step Junos troubleshooting: BGP flaps, L2 loops, interface errors and log analysis.
The EX alarm /var partition usage is high usually means leftover install images, old package sets after an upgrade, runaway logs or core dumps. This guide gives the checks in order, ranks the causes by how often they happen, and shows which files are safe to delete and which are not.
When Junos DHCP relay is not working, the drop counters in show dhcp relay statistics usually name the cause. This guide explains each counter, gives checks in order from cheapest to most expensive, and ranks the causes by how often they happen. It includes copy-ready EX and SRX configs and shows healthy output.
A Junos irb interface down with the Hardware-Down flag is a Layer 2 problem. The IRB only comes up when its VLAN or bridge domain has at least one member port that is up and forwarding. This guide gives the checks in order, ranks the causes, and shows healthy and broken output.
'High memory utilization on our core switch' is a permanent r/Juniper thread — and the JTAC answer surprises people: EX4600/EX4300 sitting at 75% is by design. Here is how to tell normal pre-allocation from a genuine leak, and the fixes for each.
Two leafs, two spines, multihomed hosts — and the ping fails. The r/Juniper EVPN-VXLAN ping issue scenario, solved methodically: underlay reachability, MAC learning, ESI multihoming, IRB gateways and overlay verification tools.
SRX security flow traceoptions show every decision the flow engine makes: session lookup, NAT, route, zone and policy. This guide covers the cheaper checks to run first, monitor security packet-drop on newer releases, how to read a trace line by line, and the root causes ranked by how often they bite.