Site-to-Site VPN: protocol selection and branch testing

IPsec is a protocol suite; IKEv2 negotiates parameters and keys, while WireGuard uses a different model. For branches, test overlapping subnets, NAT, routes, failover and key revocation.

Site-to-Site VPN links two or more IP networks, letting hosts in Branch A access resources in Branch B as if they were on the same local network or routed core. The tunnel encapsulates and encrypts packets over the public internet or an L3 channel.

Practical checks

Start with an inventory of users, applications, branches and data flows. Assign access ownership and responsibility for revoking privileges. A VPN supplies a network channel; it does not replace device management, identity, resilience or an assessment of applicable requirements. Do not promise legal compliance based only on a protocol or server country.

Verify compatibility of the exact gateway, client and identity-provider versions before rollout. Allow only required routes and roles; successful authentication must not open the entire network. Use supported MFA, certificate verification and protected secrets storage. Confirm integrations in product documentation rather than assuming support from a technology name.

Pilot with a limited group and test resources. Check normal login, denied access, device changes, user revocation, node failure and recovery. Agree acceptance criteria first: recovery time, permitted loss, application availability and log completeness. Keep the original configuration and a step-by-step rollback. Define the minimum log fields, retention and viewer permissions; avoid unnecessary collection of user traffic content.

Official documentation

• WireGuard
• strongSwan