Change Details

We have two routers: - Router-002 = BACKUP - Router-003 = MASTER --> They share the same IP address (VIP) Normally : Only the MASTER should speak ✔ The BACKUP should remain silent ❌ But with CARP + OSPF: 💥 BOTH speak at the same time > OSPF allows routers to exchange information to determine the best route for network traffic. It works by regularly exchanging messages between routers to maintain an up-to-date view of the network. In an environment with two high-availability routers, OSPF can cause problems because both routers can send these messages simultaneously using the same IP address (VIP). This creates a conflict, as the network no longer knows which router is the correct one, resulting in unstable connections. `IPsec enforces a single secure association per VIP, preventing the BACKUP node from establishing a concurrent tunnel and thus avoiding conflicts.` `So IPsec must be configured on both nodes with required policies, ensuring that only the MASTER node can establish the GRE tunnel while the BACKUP is prevented from sending traffic.` -------------------- references : https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=166462

We have two routers: - Router-002 = BACKUP - Router-003 = MASTER --> They share the same IP address (VIP) Normally : Only the MASTER should speak ✔ The BACKUP should remain silent ❌ But with CARP + OSPF: 💥 BOTH speak at the same time > OSPF is a dynamic routing protocol that allows routers to exchange routing information and automatically determine the best path for network traffic. It works by regularly sending Hello packets between routers to maintain neighbor relationships and keep an up-to-date view of the network topology. In an environment with two high-availability routers, OSPF can cause problems because both routers can send routing information simultaneously using the same IP address (VIP). This creates a conflict, as the network no longer knows which router is the correct one, resulting in unstable connections. `IPsec enforces a single secure association per VIP, preventing the BACKUP node from establishing a concurrent tunnel and thus avoiding conflicts.` `So IPsec must be configured on both nodes with required policies, ensuring that only the MASTER node can establish the GRE tunnel while the BACKUP is prevented from sending traffic.` -------------------- references : https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=166462

We have two routers: - Router-002 = BACKUP - Router-003 = MASTER --> They share the same IP address (VIP) Normally : Only the MASTER should speak ✔ The BACKUP should remain silent ❌ But with CARP + OSPF: 💥 BOTH speak at the same time > OSPF is a dynamic routing protocol that allows routers to exchange routing information ton and automatically determine the best routepath for network traffic. It works by regularly exchangsending messagesHello packets between routers to maintain neighbor relationships and keep an up-to-date view of the network topology. In an environment with two high-availability routers, OSPF can cause problems because both routers can send these messages routing information simultaneously using the same IP address (VIP). This creates a conflict, as the network no longer knows which router is the correct one, resulting in unstable connections. `IPsec enforces a single secure association per VIP, preventing the BACKUP node from establishing a concurrent tunnel and thus avoiding conflicts.` `So IPsec must be configured on both nodes with required policies, ensuring that only the MASTER node can establish the GRE tunnel while the BACKUP is prevented from sending traffic.` -------------------- references : https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=166462