Cisco Password Types 7, 5, 8, 9: Audit and Migrate on IOS XE
Built in my home lab on IOS XE 17.18: decoded every Type 7 password in seconds, migrated to Type 8, and broke Type 6 by removing the master key.
OSPF
Open Shortest Path First, the link-state IGP behind most enterprise networks. Articles tagged OSPF cover neighbor relationships, LSA types, areas, DR/BDR election, and Cisco IOS XE configuration.
Latest posts
CoPP Dropping OSPF Hellos: Neighbor Down in class-default
Built in my home lab on IOS XE 17.18: a strict CoPP policy policed OSPF together with an ICMP flood, the neighbor went down, and one routing class fixed it.
Adding a Subnet to IPsec: Crypto Map ACL vs SVTI Route
Adding a subnet to an IPsec VPN on the same IOL routers took mirrored crypto ACL edits and a second ESP pair with a crypto map, but one OSPF line with SVTI. Follow both changes, the failed transform-fault attempt, the destination typo, and verified GCM recovery.
Cisco ZBF Self Zone: Why One Zone-Pair Broke OSPF and BGP
SSH stayed reachable while unicast OSPF and loopback eBGP failed on IOSv. This Containerlab home lab follows the timer expiries, ineffective OSPF inspection, reverse-policy trap, and verified repair with OSPF pass and stateful TCP/ICMP.
OSPF Hello Packets Explained with a Real Capture
Every OSPF adjacency you have ever built started with a Hello packet, and almost every adjacency that refuses to build is a Hello packet being quietly thrown away. The trouble is that show ip ospf neighbor only tells you the
Spine-Leaf Underlay with OSPF on Nexus
A spine-leaf underlay should be the least interesting part of your fabric. Here is the OSPF build that gets you there, with real Nexus output.
OSPF Stuck in INIT: Diagnosing the One-Way Hello
INIT means "I hear you, you do not hear me". One router shows a neighbor in INIT, the other shows an empty table, and that asymmetry is the entire diagnosis. Captured live on IOS XE 17.18.2 in CML with an inbound ACL eating OSPF in one direction.
OSPF on the Cisco ASA: Areas, Redistribution, and the ASA's Quirks
The full OSPF build on a Cisco ASA: configuration, a verified adjacency with MD5 authentication, the DR/BDR election the firewall loses, the link-state database, and redistribution, all captured from a live ASAv 9.24.
IGP Migration: Moving from EIGRP to OSPF Without an Outage
Migrate a live network from EIGRP to OSPF without dropping a packet: run both protocols side by side, then flip administrative distance one command at a time. The ships in the night technique with real lab output.
Multi-Protocol Redistribution: The CCIE Scenarios That Break Networks
Two-point redistribution is where networks go to die. This article builds the classic CCIE failure for real in a CML lab, shows a route being re-injected into the protocol it came from, and then fixes it with the exact output at each step.
Expert OSPF Troubleshooting: Five Broken Scenarios, Ticket Style
Five OSPF faults built and broken for real in a CML lab, ticket style: the symptom, the two commands to compare, the actual output, and the fix for each one. OSPF rarely tells you what is wrong; this method finds it anyway.
OSPF Path Preference: O vs O IA vs E1 vs E2 vs N1 vs N2, Proven in the Lab
OSPF compares route types before metrics, so a worse metric routinely wins. Prove the full O, O IA, E1, N1, E2, N2 ordering by injecting the same prefix six different ways into a live CML topology and watching each one take over.