OpenSIPS vs Kamailio vs Homer: Choosing the Right VoIP Proxy in 2026

#!OPENSIPS_CFG_VERSION 2.4

# ── Modules ──────────────────────────────────────────────────────
loadmodule "proto_udp.so"
loadmodule "proto_tcp.so"
loadmodule "signaling.so"
loadmodule "sl.so"
loadmodule "tm.so"
loadmodule "dispatcher.so"
loadmodule "sipcapture.so"   # Homer HEP output

# ── Module params ─────────────────────────────────────────────────
modparam("dispatcher", "db_url", "mysql://opensips:pass@localhost/opensips")
modparam("dispatcher", "ds_ping_method", "OPTIONS")
modparam("dispatcher", "ds_ping_interval", 10)
modparam("dispatcher", "ds_probing_mode", 1)  # probe inactive gateways

# Send HEP to Homer on port 9060
modparam("sipcapture", "capture_node", "opensips-node-1")
modparam("sipcapture", "hep_capture_id", 1)

# ── Route logic ───────────────────────────────────────────────────
route {
    # Mirror to Homer
    sip_capture("homer.internal:9060");

    # Only process INVITEs for load balancing
    if (!is_method("INVITE")) {
        sl_send_reply("405", "Method Not Allowed");
        exit;
    }

    # Load balance across dispatcher group 1 (FreeSWITCH cluster)
    # Algorithm 4 = round-robin with failover
    if (!ds_select_dst("1", "4")) {
        sl_send_reply("503", "Service Unavailable");
        exit;
    }

    # Enable stateful transaction
    t_on_failure("MANAGE_FAILURE");

    # Forward to selected FreeSWITCH node
    t_relay();
    exit;
}

failure_route[MANAGE_FAILURE] {
    # On failure, try next available gateway
    if (t_is_canceled()) { exit; }

    if (t_check_status("503") || t_check_status("408")) {
        if (ds_next_dst()) {
            t_on_failure("MANAGE_FAILURE");
            t_relay();
            exit;
        }
    }
    sl_send_reply("503", "All gateways unavailable");
}

#!KAMAILIO

# ── Module loading ─────────────────────────────────────────────────
loadmodule "sl.so"
loadmodule "tm.so"
loadmodule "rr.so"
loadmodule "maxfwd.so"
loadmodule "usrloc.so"
loadmodule "registrar.so"
loadmodule "auth.so"
loadmodule "auth_db.so"
loadmodule "websocket.so"  # WebRTC WebSocket transport
loadmodule "topos.so"      # Topology hiding
loadmodule "siptrace.so"   # HEP to Homer

# ── Module parameters ─────────────────────────────────────────────
modparam("auth_db", "db_url", "mysql://kamailio:pass@localhost/kamailio")
modparam("auth_db", "user_column", "username")
modparam("auth_db", "password_column", "password")

# WebSocket configuration
modparam("websocket", "keepalive_mechanism", 1)
modparam("websocket", "keepalive_interval", 10)

# TOPOS — hide internal Via and Contact from external parties
modparam("topos", "db_url", "mysql://kamailio:pass@localhost/kamailio")

# HEP to Homer
modparam("siptrace", "duplicate_uri", "sip:homer.internal:9060")
modparam("siptrace", "hep_mode_on", 1)
modparam("siptrace", "hep_version", 3)
modparam("siptrace", "trace_on", 1)

# ── Request routing ────────────────────────────────────────────────
request_route {
    # Mirror to Homer for monitoring
    sip_trace();
    sip_trace_mode("t");

    # Max forwards check
    if (!mf_process_maxfwd_header("10")) {
        sl_send_reply("483", "Too Many Hops");
        exit;
    }

    # Handle REGISTER
    if (is_method("REGISTER")) {
        if (!auth_check("$fd", "subscriber", "1")) {
            auth_challenge("$fd", "0");
            exit;
        }
        save("location");
        exit;
    }

    # Route INVITEs to the OpenSIPS routing tier
    if (is_method("INVITE")) {
        record_route();
        topos_record_route();  # Topology hiding
        route(RELAY);
    }
}

route[RELAY] {
    # Forward to OpenSIPS application routing tier
    $du = "sip:opensips.internal:5060";
    t_relay();
}