GRE Tunnel Keepalives Explained
Cisco GRE keepalives explained: mechanism, configuration, IPsec rekey interactions, vendor interop, and the 30-second failover default that just works
7 min read
GRE
Generic Routing Encapsulation, the simple tunneling protocol that sits behind countless enterprise overlays. Articles tagged GRE cover how it works, packet format, Cisco IOS XE configuration, keepalives, MTU, GRE over IPsec, and routing protocol support.
9 posts
GRE over IPsec: When and How to Combine Them
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.
7 min read
GRE Tunnel Configuration: Step-by-Step Cisco IOS XE Lab
Build a GRE tunnel between two Cisco IOS XE routers step by step: tunnel interface, MTU, keepalives, OSPF over the tunnel, and recursive-routing fix.
9 min read