Site-to-site VPN allows networks in different locations to communicate over the internet through a protected tunnel. In inter-branch VPN design, address conflicts, access permissions, line conditions and the behavior of applications in case of failure should be evaluated together.
Why should the address plan of two branches be examined?
If both locations use the same local addresses, routing and access may become more complex than expected. Before creating the tunnel, register the subnets, servers, and user groups that will access. Address editing or special solution requirements should be determined at this stage.
Describe the VPN need in terms of the application and the user, rather than “let two offices see each other”. If a branch only needs to access the file application, it is not necessary for all networks to be opened mutually.
Why might the app not work when the tunnel appears to be standing?
Installing a VPN does not indicate that the routing, name resolution and security permissions required by the application have been completed. The path from the client to the target server and back should be examined separately. Access limits on the server side of the application are also added to the testing list.
Don't accept just by ping test. Try the user's actual login and file operation with the relevant application principal. Run these tests with sample processes that do not put production data at risk.
What do backup lines and backup VPN change?
When there is more than one internet line, it should be planned which way the tunnel will be established and how it will be restored after failure. Fortinet's redundant VPN example shows that alternate routes are configured separately; The menu and options are controlled according to the installed version.
Technical reference: Fortinet — Redundant VPN plan.
Don't assume that old sessions will automatically persist after the migration. Test application reconnection and external IP based restrictions in real scenario.
What should be included in the delivery file?
- Locations, subnets, and permitted application flows.
- Version information and access administrators of end devices.
- Main/backup road behavior and fault testing performed.
- Steps to restore with configuration backup.
Depending on the number of branches, network plan and application needs firewall and VPN management You can request a review within the scope of
Related resources
Official sources
Technical documentation and legislation may change; The relevant version and current text should be checked before application.
Frequently Asked Questions
Does VPN increase internet speed?
VPN is not a speed boost method. Latency, bandwidth, and capacity of end devices affect application performance.
Is inter-branch VPN and remote VPN the same?
Their purposes are different. One connects networks; the other manages the user's access to certain resources.