Step-by-step Junos troubleshooting: BGP flaps, L2 loops, interface errors and log analysis.
An SRX in flow mode creates a session, the policy matches, and show security flow session still shows Out: Pkts: 0. This guide walks through the real diagnostic order and the root causes that actually cause it, ranked by how often they show up in the field.
VRRP or SBC failover in an EVPN-VXLAN fabric stops working because the new active node's MAC address gets stuck as a duplicate and traffic keeps flooding to the old location. This guide walks through the real root causes in order of frequency and the exact commands to fix and prevent it.
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.