I have installed squid with: apt-get install squid Now I want to configure authentication ntlm, but I obtain the error: 'unrecognised ntlm auth scheme parameter 'mac-challenge-lifetime' I suposse the problem is the installation not include scheme ntlm, if i want to configure this scheme: do i have to install again squid from the sources and configure suitably? Does it exit another way to install squid with ntlm support?