Home > Articles

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

SSL Configuration

The previous sections introduced the (not-so-basic) concepts behind SSL and you have learned how to generate keys and certificates. Now, finally, you can configure Apache to support SSL. mod_ssl must either be compiled statically or, if you have compiled as a loadable module, the appropriate LoadModule directive must be present in the file.

If you compiled Apache yourself, a new Apache configuration file, named ssl.conf, should be present in the conf/ directory. That file contains a sample Apache SSL configuration and is referenced from the main httpd.conf file via an Include directive.

If you want to start your configuration from scratch, you can add the following configuration snippet to your Apache configuration file:

Listen 80
Listen 443 
<VirtualHost _default_:443>
ServerName http://www.example.com
SSLEngine on
SSLCertificateFile \
/usr/local/ssl/install/openssl/certs/http://www.example.com.cert
SSLCertificateKeyFile \
/usr/loca/ssl/install/openssl/certs/http://www.example.com.key
</VirtualHost>

With the previous configuration, you set up a new virtual host that will listen to port 443 (the default port for HTTPS) and you enable SSL on that virtual host with the SSLEngine directive.

You need to indicate where to find the server's certificate and the file containing the associated key. You do so by using SSLCertificateFile and SSLCertificateKeyfile directives.

Starting the Server

Now you can stop the server if it is running, and start it again. If your key is protected by a pass phrase, you will be prompted for it. After this, Apache will start and you should be able to connect securely to it via the https://http://www.example.com/ URL.

If you compiled and installed Apache yourself, in many of the vendor configuration files, you can see that the SSL directives are surrounded by an <IfDefine SSL> block. That allows for conditional starting of the server in SSL mode. If you start the httpd server binary directly, you can pass it the -DSSL flag at startup. You can also use the apachectl script by issuing the apachectl startssl command. Finally, if you always want to start Apache with SSL support, you can just remove the <ifDefine> section and start Apache in the usual way.

If you are unable to successfully start your server, check the Apache error log for clues about what might have gone wrong. For example, if you cannot bind to the port, make sure that another Apache is not running already. You must have administrator privileges to bind to port 443; otherwise, you can change the port to 8443 and access the URL via https://http://www.example.com:8443.

Configuration Directives

mod_ssl provides comprehensive technical reference documentation. This information will not be reproduced here; rather, I will explain what is possible and which configuration directives you need to use. You can then refer to the online SSL documentation bundled with Apache for the specific syntax or options.

Algorithms

You can control which ciphers and protocols are used via the SSLCipherSuite and SSLProtocol commands. For example, you can configure the server to use only strong encryption with the following configuration:

SSLProtocol all
SSLCipherSuite HIGH:MEDIUM

See the Apache documentation for a detailed description of all available ciphers and protocols.

Client Certificates

Similarly to how clients can verify the identity of servers using server certificates, servers can verify the identity of clients by requiring a client certificate and making sure that it is valid.

SSLCACertificateFile and SSLCACertificatePath are two Apache directives used to specify trusted Certificate Authorities. Only clients presenting certificates signed by these CAs will be allowed access to the server.

The SSLCACertificateFile directive takes a file containing a list of CAs as an argument. Alternatively, you could use the SSLCACertificatePath directive to specify a directory containing trusted CA files. Those files must have a specific format, described in the documentation. SSLVerifyClient enables or disables client certificate verification. SSLVerifyDepth controls the number of delegation levels allowed for a client certificate. The SSLCARevocationFile and SSLCARevocationPath directives enable you to specify certificate revocation lists to invalidate certificates.

Performance

SSL is a protocol that requires intensive calculations. mod_ssl and OpenSSL allow several ways to speed up the protocol by caching some of the information about the connection. You can cache certain settings using the SSLSessionCache and SSLSessionCacheTimeout directives. There is also built-in support for specialized cryptographic hardware that will perform the CPU-intensive computations and offload the main processor. The SSLMutex directive enables you to control the internal locking mechanism of the SSL engine. The SSLRandomSeed directive enables you to specify the mechanism to seed the random-number generator required for certain operations. The settings of both directives can have an impact on performance.

Logging

mod_ssl hooks into Apache's logging system and provides support for logging any SSL-related aspect of the request, ranging from the protocol used to the information contained in specific elements of a client certificate. This information can also be passed to CGI scripts via environment variables by using the StdEnvVars argument to the Options directive. You can get a listing of the available SSL variables at http://httpd.apache.org/docs-2.0/ssl/ssl_compat.html.

The SSLOptions Directive

Many of these options can be applied in a per-directory or per-location basis. The SSL parameters might be renegotiated for those URLs. This can be controlled via the SSLOptions directive.

The SSLPassPhraseDialog directive can be used to avoid having to enter a pass phrase at startup by designating an external program that will be invoked to provide it.

Access Control

The SSLRequireSSL directive enables you to force clients to access the server using SSL. The SSLRequire directive enables you to specify a set of rules that have to be met before the client is allowed access. SSLRequire syntax can be very complex, but itallows an incredible amount of flexibility. Listing 17.1 shows a sample configuration from the mod_ssl documentation that restricts access based on the client certificate and the network the request came from. Access will be granted if one of the following is met:

  • The SSL connection does not use an export (weak) cipher or a NULL cipher, the certificate has been issued by a particular CA and for a particular group, and the access takes place during workdays (Monday to Friday) and working hours (8:00 a.m. to 8:00 p.m.).

  • The client comes from an internal, trusted network.

You can check the documentation for SSLRequire for a complete syntax reference.

Listing 17.1 SSLRequire Example

SSLRequire (  %{SSL_CIPHER} !~ m/^(EXP|NULL)-/ \
      and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \
      and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \
      and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \
      and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20    ) \
      or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/

Reverse Proxy with SSL

Although at the time this book was written the SSL reverse proxy functionality was not included in mod_ssl for Apache 2.0, it is likely to be included in the future. That functionality enables you to encrypt the reverse proxy connection to backend servers and to perform client and server certificate authentication on that connection. The related directives are SSLProxyMachineCertificatePath, SSLProxyMachineCertificateFile, SSLProxyVerify, SSLProxyVerifyDepth, SSLProxyCACertificatePath, SSLProxyEngine, and SSLProxyCACertificateFile. Their syntax is similar to their regular counterparts. You can find more information about the Apache reverse proxy in Hour 15.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT 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 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 InformIT. 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.informit.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