Admin Network Technologies Raspberry Pi

A nice alternative to for the DIY linux crowd


I was building some infrastucture around automated tests using speedtest-cli. I noticed the assigned servers keep changing, some servers are categorized as malicious sources, some time out if tested on the hour and half-hour, and results are inconsistent depending on which server you get.

So, I saw that the speedtest-cli (linux command-line python script) has a switch for a “mini” server. When I investigated that seemed the answer to the problem – you can set up your own mini server and use that for yuor tests. I.e., control both ends of the test. great.

The mini server was discontinued in 2017! There’s some commercial replacement. So I thought. Forget that. I was disillusioned and then happened upon a breath of fresh air – an open source alternative to Enter, librespeed.

Some details

librespeed has a command-line program whih is an obvious rip-off of speedtest-cli. In fact it is called librespeed-cli and has many similar switches.

There is also a server setup. Really, just a few files you can put on any apache + php web server. There is a web GUI as well, but in fact I am not even that interested in that. And you don’t need to set it up at all.

What I like is that with the appropriate switches supplied to librespeed-cli, I can have it run against my own librespeed server. In some testing configurations I was getting 500 Mbps downloads. Under less favorable circumstances, much less.

Testing, testing, testing

I tested between Europe and the US. I tested through a proxy. I tested from the Azure cloud to an Amazno AWS server. I tested with a single cpu linux server (good old either as server, or as the client. This was all possible because I had full control over both ends.

Some tips
  1. Play with the speedtest-cli switches. See what works for you. librespeed-cli -h will shows you all the options.
  2. Increasing the stream count can compensate for slower PING times (assuming both ends have a fast connection)
  3. It does support proxy, but
  4. Downloads don’t really work through proxy if the server is only running http
  5. Counterintuitively, the cpu burden is on the client, not the server! My servers didn’t show the slightest bit of resource usage.
  6. Corollary to 5. My 4-cpu client to 1-cpu server test was much faster than the other way around where server and client roles were reversed.
  7. Most things aren’t sensitive to upload speeds anyway so seriously consider suppressing that test with the appropriate switch. Your tests will also run a lot faster (18 seconds versus 40 seconds).
  8. Worried about consuming too much bandwidth and transferring too much data? I also developed a solution for that (will be my next blog post)
  9. So I am running a librespeed server on my little VM on Amazon AWS but I can’t make it public for fear of getting overrun.
  10. ISPs that have excellent interconnects such as the various cloud providers are probably going to give the best results
  11. It is not true your web server needs write access to its directory in my experience. As long as you don’t care about sharing telemetry data and all that.
  12. To emphasize, they supply the speedtest-cli binary, pre-built, for a whole slew of OSes. You do not and should not compile it yourself. For a standard linux VM you will want the binary called librespeed-cli_1.0.9_linux_386.tar.gz
Example files

The point of these files is to test librespeed-cli, from the directory where you copied it to, against your own librespeed server.


"name":"ns6, Germany (active-servers)",

# see ./librespeed-cli -help for all the options
./librespeed-cli --local-json json-ns6 --server 864 --simple --no-upload --no-icmp --ipv4 --concurrent 4 --skip-cert-verify

Purpose: are we getting good speeds?

My purpose in what I am constructing is to verify we are getting good download speeds. I am not trying to hit it out of the park. That consumes (read, wastes) a lot of resources. I am targeting to prove we can achieve about 150 Mbps downloads. I don’t know anyone who can point to 150 Mbps and honestly say that’s insufficient for them. For some setups that may take four simultaneous streams, for others six. But it is definitely achievable. By not going crazy we are saving a lot of data transfers. AWS charges me for my network usage. So a six stream download test at 150 Mbps (Megabits per second) consumes about 325 MBytes download data. If you’re not being careful with your switches, you can easily nudge that up to 1 GB downloads for a single test.

My librespeed client to server tests ran overnight alongside my old approach using speedtest. The speedtest results are all over the place, with a bunch of zeroes for whatever reason, as is typical, while librespeed – and mind you this is from a client in the US, going through a proxy, to a server in Europe – produced much more consistent results. In one case where the normal value was 130 mbps, it dipped down to 110 mbps.

Testing it out at home
Test from a home PC against my own librespeed server

I made my test URL on my AWS server private, but a public one is available at

At home of course I want to test with a Raspberry Pi since I work with them so much. There is indeed a pre-built binary for Raspberry Pi. It is

The problem with speedtest in more detail

There were two final issues with speedtest that were the straws that broke the camel’s back, and they are closely related.

When you resolve it hits a Content Distribution Network (CDN), and the returned results vary. For instance right now we get:

; IN A

Note that you can also run speedtest-cli with the –list switch to get a list of speedtest servers. So in my case I found some servers which procuced good results. There was one where I even know the guy who runs the ISP and know he does an excellent job. His speedtest server is 15 miles away. But, in its infinite wisdom, speedtest sometimes thinks my server is in Lousiana, and other times thinks it’s in New Jersey! So the returned server list is completely different for the two cases. And, even though each server gets assigned a unique number, and you can specify that number with the –server switch, it won’t run the test if that particular server wasn’t proposed to you in its initial listing. (It always makes a server listing call whether you specified –list or not, for its own purposes as to which servers to use.)

I tried to use some of tricks to override this behaviour, but short of re-writing the whole thing, it was not going to work. I imagined I could force speedtest-cli to always use a particular IP address, overwriting the return from the fastly results, but getting that to work through proxy was not feasible. On the other hand if you suck it up and accept their randomly assigned server, you have to put up with a lot of garbage results.

So set up your own server, right? The –mini switch seems built to accommodate that. But the mini server was discontinued in 2017. The commercial replacement seemed to have some limits. So it’s dead end upon dead end with


An open source alternative to’s speedtest-cli has been identified and tested, both server and client. It is librespeed. It gives you a lot more control than speedtest, if that is your thing and you know a smidgeon of linux.

References and related

Just to do your own test with your browser the way you do with


librespeed-cli binaries download page:

RPi version of librespeed-cli:

The RPi I use for automatically power cycling my cable modem is hard-wired to my router and makes for an excellent platform from which to conduct these speedtests.

librespeed server:

If, in spite of every positive thing I’ve had to say about librespeed, you still want to try the more commercial speedtest-cli, here is that link:

Network Technologies Web Site Technologies

Fail: What I’m working on now: Poor man’s version of

Now that I have a dual-band router I wanted to run some tests to see if 5 GHz is really faster and more stable than 2.4 GHz, as my intuition was telling me. But my only 5 GHz device where I had a chance to measure was my amazon Fired HD tablet, and wouldn’t you know that it’s incapable of running speedtest ( The web site forced it to a mobile app version, but amazon’s app store, being limited in its offerings, doesn’t have a speedtest app!

Anyway runs ads pretty aggressively, which I don’t like.

So I decided to try to write my own.

This turned out to be very hard to do. It turns out I suck at Javascript.

Some details
Normally I show all my false starts in the hopes that others can learn frmo my mistakes, but my Javascript blunders are just too painful and I never did sort them out. When I use javascript methods to set page timers I got completely inconsistent and hence unreliable results. So I settled on this simplistic PHP approach to gauge download speed:

// - DrJ 3/2017
// the weakness of this method is that it is a single stream
echo "Date: " . date('h:i:s') . "<br-->\n";
$starttime = microtime(true);
for ($x = 0; $x &lt; 750000; $x++) {
  $string .= mt_rand(1000000,9999999);
echo "<!-- $string -->\n";
//start again
//echo date('h:i:s');
echo "
$endtime = microtime(true);
$timediff = $endtime - $starttime;
$timediff = $timediff;
//echo "php timer: starttime: " . $starttime . " endtime: " . $endtime . " diff: " . $timediff . "
echo "Page load time: " . $timediff . " s
// 1.04 is observed overhead of IP + tcp. try ip -s link show eth0 before and after running curl
$dataset = 1.04*(strlen($string) + 200)/1000000.0;
$mbps = $dataset*8.0/$timediff;
echo "Mbytes downloaded in test: " . $dataset . " Mbytes
echo "Bandwidth: " . $mbps ." mbps

I called the file index.php and put it on my server in a directory of my choosing, let’s say, downloadtimer, and run it. The results look like this:

Date: 07:30:33
Page load time: 6.9666068553925 s
Mbytes downloaded in test: 5.460208 Mbytes
Bandwidth: 6.270149142432 mbps
Test again

I pretty much gave up. Use instead. It’s much better than There is also a mobile app for

References and related

I just leanred there is a linux script (written in python) which runs speedtest! That is awesome. It is speedtest-cli

It gives you the download speed, the upload speed. It calculates the closest server. It is really the full monty.

Everyone uses

I just learned about speedcheck (speedcheck dot org). Initially it seemed promising but too often it simply doesn’t work. And its advertising is just about as aggressive as Okla’s that everyone uses.

Meanwhile a friend pointed out a couple superior speed test web sites. At&t’s Speedtest is a good choice. There are few if any ads, and it runs on my Fire HD tablet and it’s fun to watch.

This one seems only slightly less aggressive than Internet Frog. Internet Frog works on my tablet but with limited functionality and a non-flashy interface.

This site is simplest of all so probably the best: It’s run by Netflix who have an obvious interest in helping users establish what their download speed is. It only displays download speed by default, but just click Show more info and you will get ping time and upload speed as well. Also, they actually explain in a transparent way what the heck they are doing: And most importantly, they don’t shower you with ads.

Want a large file to experiment with downloading? speed test has a variety through an FTP server: . On linux I use a command like this:

$ curl > /dev/null

 % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 50.0M  100 50.0M    0     0  6099k      0  0:00:08  0:00:08 --:--:-- 11.3M

For faster speeds you should download the larger files.

I have also just discovered this site with large files you can download with HTTP:

For instance here is a direct link to their 100MB file which is nice to work with: