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.
VPN
Site-to-site and remote-access VPN across Cisco platforms. Articles tagged VPN cover tunnel design, encryption choices, routing over the overlay, and how to prove traffic is actually protected.
Latest posts — page 3
IPsec Explained: IKE Phase 1, Phase 2, and What Actually Gets Encrypted
What an SA is, why IKE runs in two phases, and which bytes of your packet actually get encrypted. Grounded in real packet captures on the transit link between two Cisco IOS XE edge routers in a CML lab.
Site-to-Site IPsec VPN with Crypto Maps on Cisco IOS XE
Complete site-to-site IPsec VPN build with crypto maps on IOS XE: ISAKMP policy, keys, transform set, interesting traffic, and the crypto map itself, with every line of CLI output captured from live cat8000v routers in CML.