How to enable Proxy setting in Maven

Considering that you have installed maven and environment variable M2_HOME is pointing to installation directory of Maven and %M2_MAVEN%/bin is appended to your environment variable %PATH%.

Open setting.xml from %M2_HOME%/conf/settings.xml. 
UnComment following code and add your Proxy Details.

<proxies>

    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>

Save file. Please note that no restart