Foglight Agent Manager 7.3.0 - Foglight Agent Manager Guide

WinRM IPv6 connection support

Starting with the Foglight Agent Manager version 5.9.1, the WinRM connection with unique local IPv6 Address and link-local IPv6 Address is supported on the Agent Manager running on Windows and Linux.

Kerberos is a network security protocol that involves three elements: the KDC, the client user, and the server with the desired service to access. The KDC is installed as part of the Domain Controller and acts as the authentication service and the ticket-granting service.

Each administrative domain has its own KDC, which contains information about the users and services for that particular domain. This administrative domain is a Kerberos realm.

The steps involved in Kerberos authentication involve the following actions:

Foglight Agent Manager always generates an auth.login.config file that is used for Kerberos. It is generated by the Agent Manager on both UNIX® and Windows®, and is used to configure the Kerberos module that the Agent Manager uses for authentication. This file is located in the <fglam_dir>/state/default/config directory, and must never be modified.

The Kerberos configuration file specifies the KDC from which tickets are obtained. Operating systems sometimes have their own Kerberos configuration files. If present, the Agent Manager uses them by default. They can be found in the following locations:

If none of these files are found, the Agent Manager attempts to create its own kerberos configuration file, based on the detected settings. The detection can only be done on Windows, and on Unix, the empty file is generated.

To detect the settings on Windows, the following environment variables are checked:

These two environment variables are only present when the user credential used to login to the machine, is a domain credential, for example, when the user account belongs to the domain. If a local user account is used, these environment variables are not present, and an attempt to generate the Kerberos configuration file is made using the network information. If not found, the empty file is generated.

If you are running the Agent Manager on a UNIX machine, to determine the values to use in the Kerberos configuration file for the remote machine, simply log in to the remote machine using a domain user credential and check the values. The format of the file is as follows:

If the Kerberos configuration file is generated by the Agent Manager, it is placed in the <fglam_dir>/state/default/config/krb5.config file, and an entry is added to the <fglam_dir>/state/default/config/fglam.config.xml file so that the Agent Manager is aware of the file location. An example of this entry on Windows is as follows:

If the file is not generated, you can generate your own file, add a value for the krb5-config-file entry in the fglam.config.xml file, and restart the Agent Manager.

NOTE: If current OS user have permission to modify krb5.config file, FglAM will automatically specify domain name as the kdc in the file if the kdc entry is not found when making Kerberos authentication.

The Kerberos configuration file typically looks like:

So for example, if connecting to a host A with user credential example.com\UserX, the kerberos file is used as follows:

In another example, if connecting to a host B with user credential other.domain\UserY, the same Kerberos file is used as follows:

To specify a non-default realm to use for the other.domain value is the second example, the Kerberos configuration file can be modified as follows

Now, if a domain of other.domain is encountered, the realm used will be OTHER.DOMAIN instead of the default_realm value since there is a domain mapping entry. This can be repeated for other domains and realms.

This is the reason that fully qualified domain names be used for the domain value of the credential. Also, to prevent any possible DNS issues with the KDC, the fully qualified name of the host should be used, such as A.example.com or B.other.domain.

There are other sections and properties that can be used in the Kerberos configuration file, but for the Agent Manager purposes, the ones described above are sufficient.

The Kerberos configuration file supports specifying multiple KDC entries in one realm, which enables the WinRM connections to try to obtain the tickets from one of these KDCs, in order to prevent the single point of failure. The multiple KDC entries configuration typically looks like:

Each KDC listed in the same realm will be tried up to <max_retries> times and each time will wait for up to <kdc_timeout> milliseconds until one succeeds.

To fix this issue, follow the instructions to achieve that total timeout number for KDC listed in the same realm does not exceed the timeout limit set by WinRM connection:

About the cross-realm negotiate authentication behavior

Cross-realm or cross-domain is the mechanism of using WinRM Negotiate authentication to establish a connection to a machine in a different domain. There are also some differences here between behavior when the Agent Manager uses Java 6 and Java 7.

Enable DNS reverse lookup

DNS reverse lookup is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual “forward” DNS lookup of an IP address from a domain name. The process of reverse resolving of an IP address uses PTR records.

The Enable DNS Reverse Lookup switch is under Dashboards > Administration > Agents > Agent Properties > FglAM > FglAMadapter.

The Basic authentication mechanism simply provides HTTP headers to the remote machine, to provide the credentials that should be used for authentication. There is no use of a configuration file or a KDC. The mechanism provides no protection for the transmitted credentials, since they are simply encoded in base64 and not encrypted or hashed. To address any security concerns, it is recommended that Basic authentication attempts are made over an HTTPS and not HTTP connection. Since the KDC is not involved in the authentication process, the credentials used for Basic authentication must be local user credentials, such as local user credentials for the remote machine, and not domain user credentials.

When the remote machine is contacted, the remote machine responds indicating that Basic authentication needs to be used by the client. The client side then base64-encodes the user name and password and sends an HTTP request with an HTTP header containing the base64-encoded result to the remote machine, which then validates the provided credential.

Since local user credentials are used, and a KDC is not needed, the domain the host is on is irrelevant for Basic authentication.

About WinRM authentication and the Agent Manager

The Agent Manager supports Basic and Negotiate WinRM authentication schemes with Windows credentials. The Negotiate authentication scheme is enabled by default in WinRM and is the recommended way to authenticate in most environments.

In order to establish connections over Windows® Remote Management (WinRM), you must provide a Windows credential. For more information, see Configuring credentials.

The Negotiate authentication scheme requires fully-qualified domain accounts. For example, instead of using the NetBIOS domain, the Windows credential should be configured with the fully qualified domain.

NOTE: When running in FIPS-compliant mode, the password for the account must be at least 14 characters (112 bits).

The Basic authentication scheme requires local Administrator accounts; you cannot use domain accounts. For more information, see Promoting remote users to administrators on local machines through the Domain Controller. Basic authentication is insecure because it transmits user names and passwords in an easily decoded string, and therefore it should not be used on an untrusted network. If Basic authentication is required, and security is a concern, configure the target system to accept only HTTPS traffic. For more information, see Manually configuring WinRM HTTPS access. If Basic authentication is not acceptable in your environment because of some specific security concerns, it can always be disabled.

Basic and Negotiate authentication schemes are not mutually exclusive when it comes to their configuration. The remote system can be enabled to use both authentication schemes, given a specific order of preference. For example, a remote machine can be configured to first attempt the Negotiate authentication, and it fails, to subsequently try the Basic authentication. Therefore, if you enable Basic authentication, there is no need to disable Negotiate authentication requests, and the other way around. However, you can disable either scheme, as required.

In general, if Basic authentication is not suitable, it should be disabled. If both Negotiate and Basic authentication are enabled, and Negotiate fails, Basic authentication is still attempted, and the credentials are transmitted in an easily decoded string. Because of different credential requirements for Negotiate (a domain user credential) and Basic (a local administrator credential), a credential only applies to one authentication type. Therefore a general recommendation is that if Basic authentication is required, Negotiate authentication does not have to be disabled. But if Negotiate authentication is needed, best practice is to disable Basic authentication requests.

You can also use Windows Group Policy Objects to automatically configure HTTP or HTTPS listeners in WinRM. For more information, see Using Group Policy Objects to configure WinRM.

You can also use the Enable WinRM authentication based on only Basic or Negotiate type switch in the FglAMAdapter Properties view to decide which WinRM authentication scheme will be used.

IMPORTANT: For WinRM connections on Windows Vista, Service Pack 1 (SP1) or later must be installed.