LibreSBC

LibreSBC is a purpose-built Session Border Controller for voice over IP networks. It is meant to sit at the network edge, the demarcation point between separate VoIP environments, where it maintains session state and lets those environments interoperate.

Connectivity covers NAT traversal, SIP normalization and header manipulation, call party translation, and protocol translation between UDP, TCP, and TLS over IPv4 and IPv6. A built-in routing engine handles load balancing, failover, and distribution, and routing can also be driven by external software over HTTP.

Security and media functions include DoS protection, topology hiding via B2BUA, TLS signaling and SRTP media encryption, access control lists, and rate limiting by calls per second and concurrent calls. It also offers codec transcoding, JSON call detail records sent to an HTTP API, and Homer capture integration. LibreSBC is built on FreeSWITCH and is licensed under MIT.