Skip to content

Configure per-connection AD SSO authentication for multi-user hosts

You can use per-connection AD SSO authentication for multi-user hosts configured to use the Firewall as a direct proxy.

Overview

This overview explains how to configure per-connection authentication for multi-user hosts. A multi-user host is an endpoint or server on which multiple users can sign in at the same time, for example, a multi-user Linux server or a Windows server running Remote Desktop services or Direct Access.

When you turn on per-connection authentication, the web proxy authenticates each HTTP or HTTPS connection from the multi-user host using an NTLM or Kerberos authentication challenge. The firewall treats all other network traffic from a multi-user host as unauthenticated – with no known user ID.

Restrictions

  • Per-connection authentication only applies for connections using direct proxy mode. You must configure browsers and other clients on the multi-user host to connect using the firewall's web proxy listening port. The default port is 3128.

  • A multi-user host with per-connection authentication configured can only use per-connection authentication. Sophos Firewall disables all other authentication methods for any traffic coming from the IP address of that host.

Note

Sophos Authentication for Thin Client (SATC) also enables Sophos Firewall to authenticate users accessing a server or remote desktop. SATC is included with Sophos Server Protection in Sophos Central and can authenticate all types of connections from end-users’ desktop sessions without requiring direct proxy configuration. See Sophos Authentication for Thin Client.

Introduction

In this example, you want to turn on per-connection AD SSO authentication for users signed in to My_Terminal_Server in the sophos.com domain. Here's the network schema.

Per-connection authentication network schema

Configuration

To use per-connection authentication for multi-user hosts, do as follows:

  1. Add an Active Directory (AD) server for authentication.
  2. Import AD groups.
  3. Set the firewall authentication method.
  4. Create an IP host for your multi-user host.
  5. Create firewall rules for inbound and outbound multi-user host traffic.

Add an AD server for authentication

When a user signs in to Sophos Firewall, it authenticates the user by verifying them against the list of users created during the integration with AD. After authenticating the user, Sophos Firewall communicates with AD to get additional authorization data for access control.

To add an AD server, do as follows:

  1. Go to Authentication > Servers and click Add.
  2. Select Active Directory as the server type.
  3. Specify the server settings.

    Note

    For settings not listed in this example, use the default settings.

    Setting Value
    Name My_AD_Server
    Server IP/domain 192.168.1.100
    Connection security SSL/TLS

    Uses the default port.
    NetBIOS domain SOPHOS
    ADS username administrator
    Password Password for the admin user of the server.
    Domain name sophos.com
    Search queries Click Add and enter dc=sophos,dc=com.

    Here's an example:

    Example AD server settings

    Tip

    Search queries are based on the domain name (DN). In this example, the domain name is sophos.com, so the search query is: dc=sophos,dc=com. See the following:

  4. Click Test connection to validate the user credentials and check the connection to the server.

  5. Click Save.

Import AD groups

When a user signs in for the first time, the firewall automatically adds them as members of the default group specified. If the user's group exists in Sophos firewall, the firewall adds the user to that group.

To import AD groups into the firewall and specify policies for them, do as follows:

  1. Go to Authentication > Servers > Manage and click Import Import button for My_AD_Server.

    Import AD group

  2. In the Import group wizard, click Start.

  3. For Base DN, select dc=sophos,dc=com.

    Import Base DN in the import group wizard

  4. Choose the AD groups you want to import. In this example, select the Marketing and KBTeam OUs.

    Tip

    Selecting an OU will select all groups within that OU.

    Select AD groups to import

  5. Select common policies for groups. Select Attach to all the Groups to assign the policies to all groups that the wizard imports.

    Select common policies for groups

  6. Review the selection.

  7. View the results and click Close.
  8. Go to Authentication > Groups and verify the recently imported groups.

Set the primary authentication method

If you've configured multiple AD servers, Sophos Firewall performs validation against your AD servers in the order configured in the web admin console.

To set the AD server as the primary authentication method, do as follows:

  1. Go to Authentication > Services.
  2. In the authentication server list under Firewall authentication methods, select My_AD_Server.
  3. Move the server to the first position in the list of selected servers.

    Here's an example:

    Authentication servers

  4. Choose the default group. Sophos Firewall adds users to the default group if they don't belong to a local group.

  5. Click Apply.

Create an IP host

You must create an IP host for your multi-user host so that you can select it for per-connection authentication.

To create an IP host for your multi-user host, do as follows:

  1. Go to Hosts and services > IP host and click Add.
  2. Specify the settings.

    Setting Value
    Name My_Terminal_Server
    IP version IPv4
    Type IP
    IP Address 192.168.1.101

    Here's an example:

    Example IP host settings

  3. Click Save.

Tip

If you have more than one multi-user host, you can create an IP host group. See Add an IP host group.

Turn on per-connection AD SSO authentication for multi-user hosts

To authenticate multiple users from a single IP address using AD SSO, you must turn on per-connection authentication for multi-user hosts. The firewall continues to use per-IP authentication for all other hosts.

To turn on per-connection authentication for multi-user hosts, do as follows:

  1. Go to Authentication > Web authentication > Authentication settings for direct web proxy.
  2. Select Use per-connection AD SSO authentication for multi-user hosts.
  3. Click Add new item and select My_Terminal_Server.
  4. Click Apply.

    Here's an example:

    Turn on per-connection authentication

Create firewall rules for multi-user host traffic

Multi-user hosts with per-connection authentication turned on must have a separate firewall rule that has Match known users turned off.

To create firewall rules for outbound multi-user host traffic, do as follows:

  1. Go to Rules and policies > Firewall rules.
  2. Select IPv4 or IPv6, select Add firewall rule, and select New firewall rule.
  3. Enter the rule details:

    Setting Value
    Rule name TS_Outbound
    Rule position Top

    Sophos Firewall evaluates rules in the order shown until it finds a match. This rule must come before other rules that affect your multi-user hosts with Match known users turned on.
    Action Accept
    Log firewall traffic Select to log all traffic that matches this rule.
  4. Specify the settings.

    Setting Value
    Source zones LAN
    Source networks and devices My_Terminal_Server
    Destination zones WAN
    Destination networks Any
    Services Select the services you want to allow.
    Match known users Turn this setting off.
  5. Enter any other settings needed for your environment. See Add a firewall rule.

  6. Click Save.

To create firewall rules for inbound multi-user host traffic, do as follows:

  1. Select IPv4 or IPv6, select Add firewall rule, and select New firewall rule.
  2. Enter the rule details:

    Setting Value
    Rule name TS_Inbound
    Rule position Top

    Sophos Firewall evaluates rules in the order shown until it finds a match. This rule must come before other rules that affect your multi-user hosts with Match known users turned on.
    Action Accept
    Log firewall traffic Select to log all traffic that matches this rule.
  3. Specify the settings.

    Setting Value
    Source zones WAN
    Source networks and devices Any
    Destination zones LAN
    Destination networks My_Terminal_Server
    Services Select the services you want to allow.
    Match known users Turn this setting off.
  4. Enter any other settings needed for your environment. See Add a firewall rule.

  5. Click Save.

More information

Back to top