Once, when running the Speedtest CLI on one Linux server, I noticed the following error:
speedtest --selection-details Speedtest by Ookla Selecting server: 2933: Failed; Thüga SmartService - Hof 4578: Failed; SWW Wunsiedel GmbH - Wunsiedel 25733: Failed; TaNET West s.r.o. - Tachov 6518: Failed; Thueringer Netkom GmbH - Weimar 11519: Failed; TELE AG - Leipzig 3313: Failed; suec//dacor GmbH - Coburg 3823: Failed; Newone - Ilmenau 6416: Failed; ForWiFi s.r.o. - Plzen 10708: Failed; PilsFree, z.s - Plzen 2495: Failed; IBH IT-Service GmbH - Dresden [error] Server Selection - Failed to find a working test server. (NoServers)
I tried to specify the speedtest server manually:
speedtest --server-id=25733 Speedtest by Ookla Server: TaNET West s.r.o. - Tachov (id = 25733) ISP: Hetzner Online GmbH [error] Failed to resolve host name. Cancelling test suite. [error] Host resolve failed: Connection refused
If you run the Speedtest CLI in verbose mode, you can see that it is trying to establish connections with the servers:
speedtest -vvv ... completed with response code 200 ... [info] Server count: 10 [info] app.version: 1.0.0.2 (5ae238b) [info] Resolving host in thread. [info] Resolving host in thread. [info] Resolving host in thread. [info] Resolving host in thread. [info] Resolved address 1: 91.137.110.250 [info] Resolving host in thread. [info] Opening socket to '91.137.110.250' [info] Resolving host in thread. [info] Resolving host in thread. [info] Resolving host in thread. [info] Resolved address 1: 109.73.31.177 [info] Opening socket to '109.73.31.177' [info] Resolving host in thread. [info] Resolved address 1: 5.61.162.244 [info] Opening socket to '5.61.162.244' ...
At the same time, the Internet on the server worked and the working DNS servers were specified in the /etc/resolv.conf file.
I found the cause of errors in the firewall, which blocked outgoing connections (OUTPUT) and after I allowed the server all outgoing connections, the Speedtest CLI started working.
See also my articles:
How to configure IPTables