Configuring Maven behind an NTLM proxy

Maven, by itself, cannot work behind an NTLM proxy (e.g. ISA servers), because this kind of HTTP connection is not supported... at least directly.

But you're not lost, since you can use a "proxy-to-the-proxy". You have two choices, CNTLM and NTLM APS.

Using CNTLM

CNTLM is easy to install and configure. Once installed as reported in the website, configure Maven to work with CNTLM, adding this code in your settings.xml.

<settings>
  <proxies>
   <proxy>
      <active>true</active>
      <protocol>http</protocol>
      <host>127.0.0.1</host>
      <port>3128</port>
    </proxy>
  </proxies>
</settings>

Et voilà! Maven works!

Using NTLM APS

NTLM has a bug with chunked responses, so you have to patch it, so I suggest to use CNTLM.

Anyway, if you want to make NTLM APS work:

download the 0.9.9.6 version of NTLM APS;
patch using this patch;
run the NTLM APS server;

configure Maven to work with NTLM APS, adding this code in your settings.xml.

<settings>
  <proxies>
   <proxy>
      <active>true</active>
      <protocol>http</protocol>
      <host>127.0.0.1</host>
      <port>5865</port>
    </proxy>
  </proxies>
</settings