IPERF3(1) User Manuals IPERF3(1) (NAME) iperf3 - TCP UDP SCTP (SYNOPSIS) iperf3 -s [ ] iperf3 -c [ ] (DESCRIPTION) iperf3 . TCP UDP SCTP . iperf3 . iperf3 . iperf3 -s --server : iperf3 -s iperf3 --server iperf3 (-s) (--server) . . iperf3 5201 TCP iperf3 . -p : iperf3 -s -p 5002 iperf3 ( iperf3 ) . -c iperf3 . IPv4 IPv6 : iperf3 -c iperf3.example.com iperf3 -c 192.0.2.1 iperf3 -c 2001:db8::1 iperf3 TCP : iperf3 -c iperf3.example.com -p 5002 TCP . << >> (control connection) . TCP UDP SCTP . () . () -R . . iperf3 -c iperf3.example.com -p 5202 -R . ( -i ). () . ( ). ( ) . -R . --get-server-output . -J JSON . JSON JSON . JSON (line-delimited JSON) JSON . iperf3 () . << (GENERAL OPTIONS)>> iperf3 iperf3 -h . (GENERAL OPTIONS) -p, --port n n ( 5201). -f, --format [kmgtKMGT] : Kbits/Mbits/Gbits/Tbits (///). -i, --interval n n . -I, --pidfile (PID). . -F, --file ( ) ( ) . . iperf3 . . --udp . -A, --affinity n/n,m (CPU affinity) ( FreeBSD ). n ( n ) . n,m (override) . ( ). -B, --bind [%] . --bind-dev . - (link-local) IPv6 - . --bind-dev . SO_BINDTODEVICE IP_BOUND_IF (root) . ( .) -V, --verbose . -J, --json JSON . --json-stream JSON . --json . --json-stream-full-output JSON JSON. --json-stream . --logfile . --forceflush (flush) . (pipe) . --timestamps[=] (timestamp) . ctime(1) . = strftime(3). = --timestamps . --rcv-timeout # (idle timeout) . ( ). --snd-timeout # TCP ( ). . . TCP_USER_TIMEOUT . --use-pkcs1-padding iperf3 . iperf3 3.17 PKCS1 RSA (side-channel attack) . iperf-3.17 OAEP iperf3 . . -m, --mptcp MPTCP . TCP MPTCP . -d, --debug (). ( ) . -v, --version . -h, --help . (SERVER SPECIFIC OPTIONS) -s, --server . -D, --daemon . -1, --one-off () . . --idle-timeout n n ( ). (one-off) . --server-max-duration n iperf . time omit time . --server-bitrate-limit n[KMGT][/n] n ( ) n . . / . --rsa-private-key-path RSA ( ) ( OpenSSL). --authorized-users-path iperf ( OpenSSL). <<>> . --time-skew-threshold ( ) . (CLIENT SPECIFIC OPTIONS) -c, --client [%] . -R . --bind-dev . - IPv6 . --sctp SCTP TCP ( FreeBSD ). TCP . -u, --udp UDP TCP. TCP . --connect-timeout n . TCP . iperf3 . -b, --bitrate n[KMGT] n ( UDP TCP/SCTP). ( -P) . '/' . << >> (burst mode) . . ( UDP ). iperf3 . --fq-rate . --bandwidth ( ) . --pacing-timer n[KMGT] (pacing timer) ( ). iperf3 -b/--bitrate . . iperf3 . --fq-rate n[KMGT] (fair-queueing) . ( ) iperf3 ( -b/--bitrate) . SO_MAX_PACING_RATE ( ). . --no-fq-socket-pacing . --fq-rate=0 . -t, --time n ( ). -t -n " " -k ( ). -n, --bytes n[KMGT] . -t -n " " -k ( ). -k, --blockcount n[KMGT] () . -t -n " " -k ( ). -l, --length n[KMGT] . TCP 128KB . UDP iperf3 MTU 1460 . SCTP 64KB . --cport TCP UDP ( TCP UDP /ephemeral ). -P, --parallel n . iperf-3.16 iperf3 (thread) . . -R, --reverse . --bidir ( ) . -w, --window n[KMGT] / (window size). . () TCP . . iperf3 tcp(7) socket(7) . -M, --set-mss n (MSS) TCP/SCTP ( MTU - 40 ). -N, --no-delay no delay TCP/SCTP (Nagle's Algorithm) . -4, --version4 IPv4. -6, --version6 IPv6. -S, --tos n IP (Type of Service). 52 064 0x34 . --dscp dscp DSCP IP. . ( --tos ). -L, --flowlabel n (flow label) IPv6 ( ). -X, --xbind SCTP sctp_bindx(3). -B . SCTP . --X . iperf ( --X bind(2) ). getaddrinfo(3) . --4 --6 . --nstreams n SCTP. -Z, --zerocopy << >> (zero copy) sendfile(2) write(2) . --skip-rx-copy MSG_TRUNC recv(2). -O, --omit n n (slow-start) TCP. -T, --title . --extra-data JSON. -C, --congestion ( FreeBSD). --linux-congestion . --get-server-output . ( --json JSON ). --json JSON . . --udp-counters-64bit UDP. UDP . 3.1 . . --gsro (GSO) (GRO) UDP ( ). GSO UDP . GSO/GRO . . --repeating-payload (payload) . iperf2 ( '0..9' ASCII). ( WiFi) iperf2 iperf3 . --dont-fragment Don't Fragment (DF) IPv4 . UDP IPv4 . --username iperf ( OpenSSL). . IPERF3_PASSWORD . . --rsa-public-key-path RSA ( OpenSSL). (EXAMPLES) - RSA iperf3 RSA . . PEM . PEM SubjectPrefixKeyInfo . UNIX/Linux OpenSSL : > openssl genrsa -des3 -out private.pem 2048 > openssl rsa -in private.pem -outform PEM -pubout -out public.pem > openssl rsa -in private.pem -out private_not_protected.pem \ -outform PEM public.pem private_not_protected.pem . - (plaintext) iperf3 . . SHA256 "{$user}$password" . ( #) . UNIX/Linux : > S_USER=mario S_PASSWD=rossi > echo -n "{$S_USER}$S_PASSWD" | sha256sum | awk '{ print $1 }' ( ) : > cat credentials.csv # file format: username,sha256 mario,bf7a49a846d44b454a5d11e7acfaf13d138bbe0b7483aa3e050879700572709b (AUTHORS) iperf3 https://software.es.net/iperf/dev.html#authors . (SEE ALSO) libiperf(3), https://software.es.net/iperf ESnet April 2026 IPERF3(1)