PHP无法访问网址

Today I set up some new PCs with Linux Mint and wanted to get my Magento-SOAP API run locally. If I run the script:

$client = new SoapClient('http://magento.dev/mageapi/v2_soap/?wsdl', array('login' => 'apiuser', 'password' => '12345678', 'cache_wsdl' => WSDL_CACHE_NONE, 'trace'=>1))

I get an error that it can't reach http://schemas.xmlsoap.org/soap/encoding/
So I tried it with:

php -r "echo file_get_contents('http://schemas.xmlsoap.org/soap/encoding/');" -d allow_url_fopen=1

If I tun it trough the local network I get the warning:

PHP Warning:  file_get_contents(http://schemas.xmlsoap.org/soap/encoding/):   
failed to open stream: HTTP request failed!  in Command line code on line 1

But If I run it through my mobile phone (via tethering) it works just fine.

It does not look like a network, but more like a local DNS-issue. On my MacBook and on my Windows device in the same network it's running fine.