[OT] Linux clientes and NTLM authentication (was: [PATCH]Authentication with NTLM proxy server)

Marcelo Magno T. Sales marcelo-sales at ig.com.br
Fri Sep 29 13:04:02 BST 2006


Taking a ride on this subject, I would like to ask if you, who have good
knowledge of NTLM authentication, if you know anything that would help me to
have applications other than browsers to authenticate against an MS ISA
Server. Preferable, in a transparent way, much like ISA Server's firewall
client for Windows. I would also be glad to hear of a 100% unix/linux
solution that allow me to restrict Internet access by user AND by application
(not only for http). Is there something?
I've tried the following so far:

1. Configure applications to use ISA Server as the proxy server.
   . Positive point: Firefox can do NTLM authentication and interoperates
 well with ISA Server.
   . Negative points: Many applications can't be configured to use proxies.
     Those which can are not able to authenticate against ISA Server.
     Even if they were, it would be necessary to configure each application
     for each user.
     In Firefox, the user have to retype his credentials every time he
     opens the browser and java applets do not
     work (JVM can't authenticate against ISA Server)

2. Use NTLMAPS / APServer on the client side
    . Positive point: Firefox can access Internet using APServer without
      requesting user credentials and java applets work fine. APServer can
      do NTLM authentication and interoperates well with ISA Server.
    . Negative points: It's usefull for HTTP access only. Other applications
      suffer from the same problems described in the previous solution.
      APServer is not user-friendly enough to be used by normal users
      and I can't configure it to start automatically (for that, I would have
      to set it up with a user account that would not match the current
 logged user).

3. Use squid on the server side
    . Positive point: HTTP access can be restricted by AD user accounts.
      squid is able to authenticate users against AD.
    . It's another HTTP-only solution. squid capabilities of restricting
      access by group are limited. Browser special configuration is

4. On the client side, use a script that creates iptables rules dinamically
    when a user logs on, according to his credentials.
    . Positive point: work for all applications. Works with ISA Server in
      NAT mode as well as with a Linux based NAT solution.
    . Negative points: administration is a nightmare. It's difficult to work
      with groups. The restrictions are enforced on the client side and
      not on the server side, what lowers down security. My network
      spans over a 800 km area, with many buildings. Each building
      has support personnel who must have local root access to the
      workstations in the building, but should not be able to set up
      their own restrictions for Internet access. It's not possible to
      prevent them from editing the local iptables rules, once they
      have root privileges at the workstations.

Is there a way to get the results I need using Linux clients?




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