SSL Custom Application

SSL Custom Application feature enables users to customize applications that run on any protocol over Secure Socket Layer (SSL), including HTTP over Secure Socket Layer (HTTPS), using the server name, if it exists in the Client Hello extensions, or the common name from the certificate that the server sends to the client.

Information About SSL Custom Application

Overview of SSL Custom Application

SSL Custom Application feature enables users to customize applications that run on any protocol over Secure Socket Layer (SSL), including HTTP over Secure Socket Layer (HTTPS), using the server name, if it exists in the Client Hello extensions, or the common name from the certificate that the server sends to the client.

HTTP over Secure Socket Layer (HTTPS) is a communication protocol for secure communication. HTTPS is the result of layering HTTP on SSL protocol.

In SSL sub-classification, the rule that ends later in the packet will match. For example, consider the server name ‘finance.example.com’, if there is a rule for ‘finance’ and another rule for example.com, then the rule for ‘example.com’ will match.

SSL Unique Name Sub-Classification

The SSL unique-name parameter is used to match SSL sessions of servers that are not known globally, or are not yet supported by NBAR. The unique-name matches the server name indication (SNI) field in the client request, if the SNI field exists, or it matches the common name (CN) field in the first certificate of the server's response.

The feature also supports cases of SSL sessions that use session-id than the SSL sessions that use handshake.

The server name is available as part of a HTTPS URL itself. For example, in the URL https://www.facebook.com, the server name is www.facebook.com. However, the certificate is found in the browser. The user can observe the certificate information by clicking on the HTTPS icon.

The following two figures display the location of the server name and common name as it is visible to the user using Wireshark tool.

The figure below highlights the location of the SNI field:

Figure 1. Server Name Indication Field


The figure below highlights the location of the CN field:

Figure 2. Common Name Field


How to Configure SSL Custom Application

Configuring SSL Custom Application

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. ip nbar custom custom-protocol-name ssl unique-name regex id selector-id
  4. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

ip nbar custom custom-protocol-name ssl unique-name regex id selector-id

Example:


Device (config)# ip nbar custom name ssl unique-name www.example.com id  11

Defines the SSL-based custom protocol match and provides a hostname in the form of a regular expression.

Note

 

The hostname that is configured in this command is found either in the Server Name Indication (SNI) field in the Client Hello extensions or in the Common Name (CN) field in the digital certificate that the server sends to the client.

Step 4

end

Example:


Router(config)# end

(Optional) Exits global configuration mode.

Configuration Examples for the SSL Custom Application

Example: SSL Custom Applications

The following example displays how to configure SSL Custom Application. The hostname that is configured in this command is found either in the Server Name Indication (SNI) field in the Client Hello extensions or in the Common Name (CN) field in the digital certificate that the server sends to the client. 


Device> enable
Device# configuration terminal
Device(config)# ip nbar custom name ssl unique-name  www.example.com id  11
Device(config)# exit

Additional References for SSL Custom Application

Related Documents for SSL Custom Application

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

SSL Sub-classification

NBAR Protocol Pack module

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for SSL Custom Application

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for SSL Custom Application

Feature Name

Releases

Feature Information

SSL Custom Application

Cisco IOS XE Release 3.15S

SSL Custom Application feature enables users to customize applications that run on any protocol over Secure Socket Layer (SSL), including HTTP over Secure Socket Layer (HTTPS), using the server name, if it exists in the Client Hello extensions, or the common name from the certificate that the server sends to the client.

The following command was introduced or modified:

ip nbar custom .