Home > Articles

  • Print
  • + Share This
This chapter is from the book

Configuring IPSec Policies

You should understand that IPSec is designed to be an end-to-end security model that secures traffic between clients and servers. The IP address of the computer does not necessarily have to be the entity that is considered; rather, the system that uses the IP address is validated through an authentication process. This allows you to deploy IPSec to a computer, domain, site, or any container within your Active Directory (AD).

In addition, because there are many ways to authenticate, IPSec can be used to secure local area network (LAN) communications, wide area network communications, and remote access communications as well. This is accomplished through the configuration of IPSec policies that contain rules and filters. The rules and filters that you use will depend on what you are securing and how much protection it requires. You should be familiar with the following configuration options using IPSec:

  • Transport mode

  • Tunnel mode

  • IPSec policy rules

Transport Mode

Transport mode is the default mode for IPSec. It is used for end-to-end security between a client and a server within a LAN. IPSec can encrypt the payload of each packet to protect the integrity and confidentiality of the data that it contains. As an alternative, IPSec can simply be used to ensure that the communication came from the indicated source and that the communication hasn't been intercepted or tampered with while in transit. Based on your own security needs, you can configure IPSec for one of the following:

  • Authentication Header (AH) transport mode

  • Encapsulating Security Payload (ESP) transport mode

Authentication Header (AH) Transport Mode

Authentication Header (AH) provides for authentication, integrity, and anti-replay of each packet without encrypting the data. In other words, the data remains readable but is protected from modification. AH uses a system of keyed hash algorithms to sign the packet to ensure its integrity. In this way, you can be assured that a packet did originate from its indicated source and that it has not been modified in transit. This is accomplished by placing an AH header in each packet between the IP header and the IP payload. You can configure custom data integrity and encryption settings, as illustrated on Figure 3.8. Configuring custom settings requires the following steps:

  1. Locate or create an IPSec policy in a computer's Local Settings, a domain's Default Security Policy, or a Group Policy Object.

  2. Right-click the IPSec policy.

  3. Click Properties.

  4. Select the Default Response rule.

  5. Click Edit.

  6. On the Security Methods tab, click Edit.

  7. Select Custom.

  8. Click Settings.

NOTE

AH does not encrypt the data within the packets sent.

Figure 3.8Figure 3.8 PSec can be used to protect the integrity of a packet using AH.

Encapsulating Security Payload (ESP) Transport Mode

Encapsulating Security Payload (ESP) provides everything that AH does and also provides for the confidentiality of the packet during transit. In transport mode, the entire packet is not encrypted or signed; rather, only the data in the IP payload is encrypted and signed. The authentication process ensures that the packet originated from the indicated sender, and the fact that the data was encrypted ensures that it wasn't viewed or modified during transit. This is accomplished by placing an ESP header before the IP payload and an ESP trailer after the IP payload, further encapsulating only the IP payload.

CAUTION

ESP does not sign the entire packet—only the IP payload itself is encrypted.

Tunnel Mode

IPSec tunnel mode encrypts the IP header and the payload during transit. In this way, tunnel mode provides protection for the entire packet. An entire IP packet is first encapsulated with an AH or ESP header, and then the result is encapsulated with an additional IP header. The additional IP header contains the source and destination of the tunnel endpoints. After the packet reaches the first destination at the tunnel endpoint, it can be decapsulated and sent to the final destination by reading the IP address.

This double encapsulation makes tunnel mode suitable for protecting traffic between network systems. It can be used when traffic must pass through an untrusted medium such as the Internet. It is therefore most often used with gateways or end-systems that do not support L2TP/IPSec or PPTP connections. You can use IPSec tunnel mode for the following configurations:

  • Gateway to gateway

  • Server to gateway

  • Server to server

As with transport mode IPSec, tunnel mode IPSec can be used in AH mode or in ESP mode. The concept is very much the same except that the packets are encapsulated twice. You can configure IPSec tunnel mode for the following:

  • AH tunnel mode

  • ESP tunnel mode

Authentication Header (AH) Tunnel Mode

AH tunnel mode encapsulates an IP packet by placing an AH header between the internal IP header and the external IP header. AH then signs the entire packet for integrity and authentication. This is illustrated in Figure 3.9.

Encapsulating Security Payload (ESP) Tunnel Mode

ESP mode encapsulates an IP packet with an ESP header, IP header, and ESP trailer. This has the effect of protecting the IP header, trailer, and payload. The entire packet is then encapsulated into a new IP tunnel header, which contains the IP addresses of the endpoints of the tunnel. This is illustrated in Figure 3.10.

TIP

Transport mode IPSec is used for secure communications between client and servers in a LAN, whereas tunnel mode is used for secure communication between networks.

Figure 3.9Figure 3.9 In AH tunnel mode, authentication headers are placed between the internal IP header and the external IP header of each packet.

Figure 3.10Figure 3.10 In ESP tunnel mode, the entire packet is encapsulated into a new IP tunnel header, which contains the IP addresses of the endpoints of the tunnel.

IPSec Policy Rules

Whether you use transport mode or tunnel mode for IPSec, the behavior of the system will be determined and controlled by the rules that you configure. Windows Server 2003 comes installed with some basic rules, but these are only to be used for examples because they offer no real security for your network. You should configure rules based on the security requirements of your organization. How you configure the rules of a policy will determine how it will be used and ultimately whether it will be in transport mode or tunnel mode.

Each IPSec policy consists of one of more rules that will determine the behavior of the policy. The rules are configured on the Rules tab of the properties of an IPSec policy, as shown in Figure 3.11. You can access the Rules tab by right-clicking a policy and clicking Properties. Each rule can contain settings for the following:

  • Filter list

  • Filter action

  • Authentication methods

  • Tunnel endpoint

  • Connection type

Figure 3.11Figure 3.11 You can configure the properties of each IPSec rule.

Filter List

You configure a filter list by selecting the IP Filter List tab in the properties of an IPSec rule (see Figure 3.12). In the resulting IP Filter List dialog box, a single filter list can contain multiple predefined packet filters that allow traffic to be identified by the list. After the traffic is identified, then the filter action can be applied. Filter lists can identify traffic based on its source, destination, and protocol. You can set both inbound and outbound filters in an IPSec policy.

Figure 3.12Figure 3.12 You can configure multiple filter lists in a single IPSec policy.

Filter Action

A filter action is set for each type of traffic as identified by a filter list. The filter actions from which you can choose include Permit, Block, or Negotiate Security for the packets that match the filter list. If Negotiate Security is selected, one or more security methods can be selected. Filter actions are configured on the Filter Action tab in the properties of an IPSec rule. As mentioned previously, the system automatically processes multiple filters in order of specificity, starting with the most specific.

Authentication Methods

You can configure one of more authentication methods to be used in main mode during negotiations. The available authentication methods (as discussed previously) are Kerberos V5, certificates, and preshared keys. You should only use preshared keys as a last resort. You can configure these using the Authentication Methods tab in the properties of an IPSec rule.

Tunnel Endpoint

When you configure a tunnel endpoint as part of a rule, you are setting up one end of tunnel mode IPSec. You must also configure the other end of the tunnel with the same rule and its corresponding tunnel endpoint. This establishes the IP addresses that will be used when the packet is encapsulated before being sent through the tunnel. You should configure the tunnel endpoint on the Tunnel Setting tab in the properties of the IPSec rule to which it applies.

Connection Type

The connection type specifies whether this rule applies to LAN communications, dial-up, or both. The connection type setting can be used to specify rules based on the inherent protocols and technologies that your connection uses. In other words, LAN communications will certainly use different protocols (rules) than dial-up communications and will therefore require different IPSec rules as well.

  • + Share This
  • 🔖 Save To Your Account

Pearson IT Certification Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Pearson IT Certification and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Pearson IT Certification products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.pearsonitcertification.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020