FreeBSD 14.3-RELEASE on amd64. Testing on both the latest package and the latest port. Let's start udpxy from command line like this: sudo udpxy -a 127.0.0.1 -p 80 -l /var/log/udpxy.log Let's suppose the multicast 234.5.2.1:1234 present and is available (checked by ffprobe). Trying to catch it: curl -v -o test.bin http://127.0.0.1/udp/234.5.2.1:1234 % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0* Trying 127.0.0.1:80... * Established connection to 127.0.0.1 (127.0.0.1 port 80) from 127.0.0.1 port 59171 * using HTTP/1.x > GET /udp/234.5.2.1:1234 HTTP/1.1 > Host: 127.0.0.1 > User-Agent: curl/8.16.0 > Accept: */* > * Request completely sent off < HTTP/1.1 400 Invalid address < Server: udpxy 1.0-25.2 (prod) standard [FreeBSD 14.3-RELEASE amd64] < Content-Type:application/octet-stream * no chunk, no close, no size. Assume close to signal end < { [0 bytes data] 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 * shutting down connection #0 udpxy log: 2026-03-02 18:37:34.467994 MSK S(15477) Got 1 requests pre-process sockets [1]: 6 2026-03-02 18:37:34.467999 MSK S(15477) acting on accepted socket [6] (1/1) 2026-03-02 18:37:34.468002 MSK S(15477) Reading command from socket [6] 2026-03-02 18:37:34.468005 MSK S(15477) HTTP buffer [91 bytes] received GET /udp/234.5.2.1:1234 HTTP/1.1 Host: 127.0.0.1 User-Agent: curl/8.16.0 Accept: */* 2026-03-02 18:37:34.468015 MSK S(15477) Request=[udp/234.5.2.1:1234], length=[18] 2026-03-02 18:37:34.468018 MSK S(15477) Command [udp] with params [234.5.2.1:1234], tail [] read from socket=[6] 2026-03-02 18:37:34.468021 MSK S(15477) udp_relay : new_socket=[6] param=[234.5.2.1:1234] 2026-03-02 18:37:34.468025 MSK S(15477) Invalid address: [^R] 2026-03-02 18:37:34.468037 MSK S(15477) Sent HTTP response code=[400], reason=[Invalid address] to socket=[6] HTTP/1.1 400 Invalid address Server: udpxy 1.0-25.2 (prod) standard [FreeBSD 14.3-RELEASE amd64] Content-Type:application/octet-stream 2026-03-02 18:37:34.468048 MSK S(15477) error [3] processing client socket [6] 2026-03-02 18:37:34.468051 MSK S(15477) process_requests: closing accepted socket [6] 2026-03-02 18:37:34.468062 MSK S(15477) Processed [1/1] accepted sockets newly-accepted sockets [1]: -1 2026-03-02 18:37:34.468067 MSK S(15477) All accepted sockets processed 2026-03-02 18:37:34.468069 MSK S(15477) Waiting for input from [2] fd's, with timeout 2026-03-02 18:37:34.468071 MSK S(15477) select() timeout set to [30] seconds Tested on different servers, the same result. udpxy built on Linux works correctly.