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Oracle Solaris Administration: Security Services     Oracle Solaris 11 Information Library
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Document Information

Preface

Part I Security Overview

1.  Security Services (Overview)

Part II System, File, and Device Security

2.  Managing Machine Security (Overview)

3.  Controlling Access to Systems (Tasks)

4.  Virus Scanning Service (Tasks)

5.  Controlling Access to Devices (Tasks)

6.  Using the Basic Audit Reporting Tool (Tasks)

7.  Controlling Access to Files (Tasks)

Part III Roles, Rights Profiles, and Privileges

8.  Using Roles and Privileges (Overview)

9.  Using Role-Based Access Control (Tasks)

10.  Security Attributes in Oracle Solaris (Reference)

Part IV Cryptographic Services

11.  Cryptographic Framework (Overview)

12.  Cryptographic Framework (Tasks)

13.  Key Management Framework

Part V Authentication Services and Secure Communication

14.  Network Services Authentication (Tasks)

15.  Using PAM

16.  Using SASL

17.  Using Secure Shell (Tasks)

18.  Secure Shell (Reference)

Part VI Kerberos Service

19.  Introduction to the Kerberos Service

20.  Planning for the Kerberos Service

21.  Configuring the Kerberos Service (Tasks)

Configuring the Kerberos Service (Task Map)

Configuring Additional Kerberos Services (Task Map)

Configuring KDC Servers

How to Automatically Configure a Master KDC

How to Interactively Configure a Master KDC

How to Manually Configure a Master KDC

How to Configure a KDC to Use an LDAP Data Server

How to Automatically Configure a Slave KDC

How to Interactively Configure a Slave KDC

How to Manually Configure a Slave KDC

How to Refresh the Ticket-Granting Service Keys on a Master Server

Configuring Cross-Realm Authentication

How to Establish Hierarchical Cross-Realm Authentication

How to Establish Direct Cross-Realm Authentication

Configuring Kerberos Network Application Servers

How to Configure a Kerberos Network Application Server

How to Use the Generic Security Service With Kerberos When Running FTP

Configuring Kerberos NFS Servers

How to Configure Kerberos NFS Servers

How to Create a Credential Table

How to Add a Single Entry to the Credential Table

How to Provide Credential Mapping Between Realms

How to Set Up a Secure NFS Environment With Multiple Kerberos Security Modes

Configuring Kerberos Clients

Configuring Kerberos Clients (Task Map)

How to Create a Kerberos Client Installation Profile

How to Automatically Configure a Kerberos Client

How to Interactively Configure a Kerberos Client

How to Configure a Kerberos Client for an Active Directory Server

How to Manually Configure a Kerberos Client

How to Disable Verification of the Ticket-Granting Ticket

How to Access a Kerberos Protected NFS File System as the root User

How to Configure Automatic Migration of Users in a Kerberos Realm

How to Configure Account Lockout

Synchronizing Clocks Between KDCs and Kerberos Clients

Swapping a Master KDC and a Slave KDC

How to Configure a Swappable Slave KDC

How to Swap a Master KDC and a Slave KDC

Administering the Kerberos Database

Backing Up and Propagating the Kerberos Database

The kpropd.acl File

The kprop_script Command

How to Back Up the Kerberos Database

How to Restore the Kerberos Database

How to Convert a Kerberos Database After a Server Upgrade

How to Reconfigure a Master KDC to Use Incremental Propagation

How to Reconfigure a Slave KDC to Use Incremental Propagation

How to Configure a Slave KDC to Use Full Propagation

How to Verify That the KDC Servers Are Synchronized

How to Manually Propagate the Kerberos Database to the Slave KDCs

Setting Up Parallel Propagation

Configuration Steps for Setting Up Parallel Propagation

Administering the Stash File

How to Remove a Stash File

How to Employ a New Master Key

Managing a KDC on an LDAP Directory Server

How to Mix Kerberos Principal Attributes in a Non-Kerberos Object Class Type

How to Destroy a Realm on an LDAP Directory Server

Increasing Security on Kerberos Servers

How to Enable Only Kerberized Applications

How to Restrict Access to KDC Servers

How to Use a Dictionary File to Increase Password Security

22.  Kerberos Error Messages and Troubleshooting

23.  Administering Kerberos Principals and Policies (Tasks)

24.  Using Kerberos Applications (Tasks)

25.  The Kerberos Service (Reference)

Part VII Auditing in Oracle Solaris

26.  Auditing (Overview)

27.  Planning for Auditing

28.  Managing Auditing (Tasks)

29.  Auditing (Reference)

Glossary

Index

Synchronizing Clocks Between KDCs and Kerberos Clients

All hosts that participate in the Kerberos authentication system must have their internal clocks synchronized within a specified maximum amount of time (known as clock skew). This requirement provides another Kerberos security check. If the clock skew is exceeded between any of the participating hosts, client requests are rejected.

The clock skew also determines how long application servers must keep track of all Kerberos protocol messages, in order to recognize and reject replayed requests. So, the longer the clock skew value, the more information that application servers have to collect.

The default value for the maximum clock skew is 300 seconds (five minutes). You can change this default in the libdefaults section of the krb5.conf file.


Note - For security reasons, do not increase the clock skew beyond 300 seconds.


Because maintaining synchronized clocks between the KDCs and Kerberos clients is important, you should use the Network Time Protocol (NTP) software to synchronize them. NTP public domain software from the University of Delaware is included in the Oracle Solaris software.


Note - Another way to synchronize clocks is to use the rdate command and cron jobs, a process that can be less involved than using NTP. However, this section focuses on using NTP. And, if you use the network to synchronize the clocks, the clock synchronization protocol must itself be secure.


NTP enables you to manage precise time or network clock synchronization, or both, in a network environment. NTP is basically a server-client implementation. You pick one system to be the master clock (the NTP server). Then, you set up all your other systems (the NTP clients) to synchronize their clocks with the master clock.

To synchronize the clocks, NTP uses the xntpd daemon, which sets and maintains a UNIX system time-of-day in agreement with Internet standard time servers. The following shows an example of this server-client NTP implementation.

Figure 21-1 Synchronizing Clocks by Using NTP

image:Diagram shows a central NTP server as the master clock for NTP clients and Kerberos clients that are running the xntpd daemon.

Ensuring that the KDCs and Kerberos clients maintain synchronized clocks involves implementing the following steps:

  1. Setting up an NTP server on your network. This server can be any system, except the master KDC. See Managing Network Time Protocol (Tasks) in Oracle Solaris Administration: Network Services to find the NTP server task.

  2. As you configure the KDCs and Kerberos clients on the network, setting them up to be NTP clients of the NTP server. See Managing Network Time Protocol (Tasks) in Oracle Solaris Administration: Network Services to find the NTP client task.