Requisites To have php with the php-xmlrpc extension enabled. To be able to edit php files to add some debugging information. It's enough to test this with php74, though it's ideal to test it also with php80. Configuration Install a moodle site In Admin -> Advanced features, enable "Networking" (On) and save changes. Navigate to http://YOURSITE/admin/mnet/index.php . Verify that you see a publick key (a long text with BEGIN CERTIFICATE... END CERTIFICATE). Click on "Delete this key" and confirm (clicking on "yes). *Verify that you're back to the page where the public key is shown and that the key has a "Valid until" being around 28 days (aprox) in the future. Copy the public key to some document (we'll use it later for some verifications). Navigate to http://YOURSITE/admin/mnet/peers.php Verify that "Register all hosts is currently" is currently OFF. Edit the mnet/xmlrpc/serverlib.php file. In the mnet_keyswap() function add this line: @@ -532,6 +532,7 @@ function mnet_keyswap($function, $params) { $mnet_peer = new mnet_peer(); list($wwwroot, $pubkey, $application) = $params; $keyok = $mnet_peer->bootstrap($wwwroot, $pubkey, $application); + error_log('KEYOK: ' . (int)$keyok); if ($keyok) { $mnet_peer->commit(); } Open a terminal to inspect the web server error logs, it should be something like: tail -f /path/to/your/web/server/error_log Download the data.xml file attached to this issue. Tests with "enable all hosts" disabled. Execute: curl -X POST -d @data.xml http://YOURSITE/mnet/xmlrpc/server.php Verify that some XML is returned and it looks like this: <methodResponse> <params> <param> <value> <string>-----BEGIN CERTIFICATE-----&#10; LONG-PUB-KEY-GOES HERE -----END CERTIFICATE-----&#10;</string> </value> </param> </params> </methodResponse> Verify that the pub key matches the pub key saved in step 7 of configuration (to verify that the first 20-30 chars are the same is enough). Verify that no KEYOK line has been printed in logs. Go to http://YOURSITE/admin/mnet/peers.php Verify that there isn't any site in the list apart from the "all hosts" one. Tests with "enable all hosts" enabled. Go to http://YOURSITE/admin/mnet/peers.php Clink on the "Turn it on" button. Verify that "Register all hosts is currently" is currently ON. Execute: curl -X POST -d @data.xml http://YOURSITE/mnet/xmlrpc/server.php Verify that some XML is returned and it looks like this: <methodResponse> <params> <param> <value> <string>-----BEGIN CERTIFICATE-----&#10; LONG-PUB-KEY-GOES HERE -----END CERTIFICATE-----&#10;</string> </value> </param> </params> </methodResponse> Verify that the pub key matches the pub key saved in step 7 of configuration (to verify that the first 20-30 chars are the same is enough). Verify that KEYOK: 1 line has been printed in logs. Verify , if your site has debugging enabled, that there is also a "cURL request" error printed in logs. That's normal, because the testing site has tried to access to http://127.0.0.1/~stronk7/integration that obviously doesn't exist in your testing environment. It's not important, because it's only used to fetch the site name. Go to http://YOURSITE/admin/mnet/peers.php Verify that there is a new site added, with URL and name http://127.0.0.1/~stronk7/integration