I have the following proxy set up in my settings.xml file
<proxy>
<id>optional</id>
<active>true</active>
<protocol>http</protocol>
<username>someusername</username>
<password>somepassword</password>
<host>some.proxy.host.com</host>
<port>5150</port>
<nonProxyHosts>localhost|127.0.0.1</nonProxyHosts>
</proxy>
But it still applies the proxy to my localhost, everytime I have to do something with localhost I have to change active to false.