In the Netbeans Options window I've set a SOCKS5 proxy in the General tab.
However when using Maven, Netbeans doesn't pass any proxy options to the mvn command line.
I have to manually add -DsocksProxyHost and -DsocksProxyPort in the Maven Global Excution Options to make it work.
Netbeans should pass the correct proxy options to Maven automatically.
*** This bug has been marked as a duplicate of bug 194916 ***