NAME¶

irtt-server - Isochronous Round-Trip Time Server

SYNOPSIS¶

irtt server [args]

DESCRIPTION¶

irtt server is the server for irtt(1) (irtt.html).

OPTIONS¶

-b addresses

Bind addresses (default “:2112”), comma separated list of:

-d duration

Max test duration, or 0 for no maximum (default 0s, see Duration units below)

-i interval

Min send interval, or 0 for no minimum (default 10ms, see Duration units below)

-l length

Max packet length (default 0), or 0 for no maximum. Numbers less than size of required headers will cause test packets to be dropped.

--hmac=key

Add HMAC with key (0x for hex) to all packets, provides:

--timeout=duration

Timeout for closing connections if no requests received on a connection (default 1m0s, see Duration units below). 0 means no timeout (not recommended, especially on public servers). Max client interval will be restricted to timeout/4.

--pburst=#

Packet burst allowed before enforcing minimum interval (default 5)

--fill=fill

Payload fill if not requested (default pattern:69727474). Possible values include:

--allow-fills=fills

Comma separated patterns of fill requests to allow (default rand). See options for –fill. Notes:

--tstamp=modes

Timestamp modes to allow (default dual). Possible values:

--no-dscp

Don't allow setting dscp (default false)

--set-src-ip

Set source IP address on all outgoing packets from listeners on unspecified IP addresses (use for more reliable reply routing, but increases per-packet heap allocations)

--gc=mode

Sets garbage collection mode (default on). Possible values:

--thread

Lock request handling goroutines to OS threads

-h

Show help

-v

Show version

SECURITY¶

Running an IRTT server that's open to the outside world requires some additional attention. For starters, irtt server's command line flags should be used to, at a minimum:

•

Restrict the duration (-d), interval (-i) and length (-l) of tests, particularly for public servers

•

Set an HMAC key (--hmac) for private servers to prevent unauthorized discovery and use

In addition, there are various systemd(1) options available for securing services. The irtt.service file included with the distribution sets many commonly used options, but should not be considered exhaustive.

To secure a server for public use, additional steps may be taken that are outside of the scope of this documentation, including but not limited to:

•

Setting up an iptables firewall (only UDP port 2112 must be open)

•

Setting up a chroot jail

It should be noted that there are no known security vulnerabilities in the Go language at this time, and the steps above, in particular the chroot jail, may or may not serve to enhance security in any way. Go-based servers are generally regarded as safe because of Go's high-level language constructs for memory management, and at this time IRTT makes no use of Go's unsafe (https://golang.org/pkg/unsafe/) package.

EXIT STATUS¶

irtt server exits with one of the following status codes:

EXAMPLES¶

$ irtt server

Starts the server and listens on all addresses (unspecified address)

$ irtt server -d 30s -i 20ms -l 256 --fill=rand --allow-fills=“”

Starts the server and listens on all addresses, setting the maximum test duration to 30 seconds, minimum interval to 20 ms, and maximum packet length to 256 bytes. Disallows fill requests and forces all return packets to be filled with random data.

$ irtt server -b 192.168.100.11:64381 --hmac=secret

Starts the server and binds to IPv4 address 192.168.100.11, port 64381. Requires a valid HMAC on all packets with the key secret, otherwise packets are dropped.

SEE ALSO¶

irtt(1) (irtt.html), irtt-client(1) (irtt-client.html)

IRTT GitHub repository (https://github.com/peteheist/irtt/)