iperf-3.20 2025-11-14

NOTE: iperf-3.20 incorporates all of the changes in prior iperf3 releases, including iperf-3.19.1.

• Notable user-visible changes

  • Millisecond-resolution representations have been added to JSON timestamps. (PR #1846)

  • The reorder_seen metric, where available, is now available in the JSON output. (PR #1278)

  • A division by zero error has been fixed. (PR #1906)

  • Some command-line options were not properly restricted to the client or server; this problem has been fixed. (#1892 / PR #1894)

  • The combination of --udp and --file is now explicitly disallowed. (PR #1909)

  • It is now possible to get both the full JSON result object as well as streaming intermediate JSON result objects. This functionality is enabled by using the new --json-stream-full command-line flag, in addition to the existing --json-stream flag (PR #1903)

  • Sends with --zerocopy are now properly seeded with data instead of being all-zeroes. (PR #1949)

  • The --server-max-duration flag is now allowed on the iperf3 server to impose a maximum duration on timed tests. (PR #1684)

  • The --rcv-timeout flag is now ignored for --bidir tests. This change prevents premature termination of bidirectional tests. (#1766 / PR #1946)

  • Several errors in the authentication code were uncovered when building with OpenSSL 3.5.3 and later versions. These were fixed. (#1951 / PR #1956)

  • Various issues in the iperf3 manual page were fixed up. (PR #1887, PR #1927, PR #1936, PR #1941, #1891 / PR #1952)

• Notable developer-visible changes

  • A build failure with uClibc has been fixed. (#1888 / PR #1890)

  • It is now possible to use the API to load RSA keys from a file. (PR #1889)

  • Some calls to sprintf() were replaced with calls to snprintf(). There were no hazards in the code as written, but this change might help silence some compiler warnings and potentially prevent future vulnerabilities. (PR #1929)

  • Proper error handling has been added to the unit_atoX() functions. (PR #1394)

  • Some memory handling errors in t_auth were fixed. (PR #1953)

  • Minor enhancements and fixes to GitHub Actions workflows (PR #1919, PR #1928, PR #1942).