OpenVPN

OpenVPN is a widely used, open-source VPN protocol with a long track record. Its great strength is flexibility: it supports many cipher and authentication options, runs over either UDP or TCP, and can be tuned for all kinds of networks. Running over TCP on port 443 lets it slip through firewalls that block other VPNs by resembling ordinary HTTPS. The trade-off for this flexibility is a larger codebase and generally lower speed than the leaner WireGuard.

OpenVPN builds an encrypted tunnel using TLS for key exchange and a negotiated cipher such as AES-256 for the data. Over UDP it is fast; over TCP it is more resilient through restrictive networks at some cost to speed. Because it can masquerade as HTTPS traffic, it is a common fallback where deep packet inspection or firewalls block UDP-based VPNs. Its maturity means broad client support on virtually every platform, part of why it remains a default choice.

s4m supports WireGuard and OpenVPN profiles. The issued profile and client routing determine the exit and which traffic follows the tunnel. s4m has selectable public exit configurations. Use the endpoint or profile issued for the protocol and location selected in your account. Routing, congestion and the target affect latency and throughput. Compare the same workload through each relevant path at several times instead of assuming predictable performance from a region. Related topics: VPN, WireGuard, no-logs, RAM-first, VPN page.