IPsec
·
NAT Traversal (NAT-T): How IPsec Survives a NAT Device
Every IPsec engineer eventually hits the same wall. The tunnel worked perfectly in the lab, you shipped the branch router,
Labs
Hands-on Cisco IOS XE lab walkthroughs. Each lab ships with a real CML topology, configs you can paste, and verified show output. Articles tagged Labs cover the full CCNA 200-301 blueprint across Network Fundamentals, Network Access, IP Connectivity, IP Services, and Security Fundamentals.
Latest
IPsec
·
GRE over IPsec: Why Tunnels and Encryption Belong Together
Configure GRE over IPsec on Cisco IOS XE with IKEv2 and IPsec profiles. Modern and legacy configs, MTU planning, OSPF over the tunnel, and gotchas.
IPsec
·
IPsec Explained: IKE Phase 1, Phase 2, and What Actually Gets Encrypted
Almost everything written about IPsec starts with a config snippet. That is backwards. If you do not know what an
IPsec
·
Site-to-Site IPsec VPN with Crypto Maps on Cisco IOS XE
A site-to-site VPN built with crypto maps is still the config the CCIE Security lab expects you to
Advanced EEM: Tcl, Multi-Event Correlation, and EEM + Python
EEM - the Embedded Event Manager - is the router's built-in automation engine, and it has been there, on
Jinja2 Templates for Network Configs: From Variables to Rendered CLI
Copying a router config, pasting it, and changing the IP addresses by hand is how configuration errors are born. Jinja2
Expert Services Troubleshooting: NAT, DHCP, and SLA Ticket Scenarios
Services break in ways that routing never does. A route either exists or it does not; a NAT translation either
IPv6
·
IPv6 Services Closure: NPTv6, DHCPv6-PD, and General Prefix
IPv6 does several things differently from IPv4, and a few of them are genuinely better - once you understand them. Prefix