Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 6.x
Configuring Keychain Management
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Configuring Keychain Management

This chapter describes how to configure keychain management on a Cisco NX-OS device.

This chapter includes the following sections:

Information About Keychain Management

Keychains and Keychain Management

Keychain management allows you to create and maintain keychains, which are sequences of keys (sometimes called shared secrets). You can use keychains with features that secure communications with other devices by using key-based authentication. The device allows you to configure multiple keychains.

Some routing protocols that support key-based authentication can use a keychain to implement a hitless key rollover for authentication. For more information, see the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide.

Lifetime of a Key

To maintain stable communications, each device that uses a protocol that is secured by key-based authentication must be able to store and use more than one key for a feature at the same time. Based on the send and accept lifetimes of a key, keychain management provides a secure mechanism to handle key rollover. The device uses the lifetimes of keys to determine which keys in a keychain are active.

Each key in a keychain has two lifetimes, as follows:

Accept lifetime

The time interval within which the device accepts the key during a key exchange with another device.

Send lifetime

The time interval within which the device sends the key during a key exchange with another device.

You define the send and accept lifetimes of a key using the following parameters:

Start-time

The absolute time that the lifetime begins.

End-time

The end time can be defined in one of the following ways:

  • The absolute time that the lifetime ends
  • The number of seconds after the start time that the lifetime ends
  • Infinite lifetime (no end-time)

During a key send lifetime, the device sends routing update packets with the key. The device does not accept communication from other devices when the key sent is not within the accept lifetime of the key on the device.

We recommend that you configure key lifetimes that overlap within every keychain. This practice avoids failure of neighbor authentication due to the absence of active keys.

Virtualization Support for Keychain Management

The following information applies to keychains used in virtual device contexts (VDCs):

  • Keychains are unique per VDC. You cannot use a keychain that you created in one VDC in a different VDC.
  • Because keychains are not shared by VDCs, you can reuse keychain names in different VDCs.
  • The device does not limit keychains on a per-VDC basis.

Licensing Requirements for Keychain Management

This table shows the licensing requirements for keychain management.

Product

License Requirement

Cisco NX-OS

Keychain management requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For an explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.

Prerequisites for Keychain Management

Keychain management has no prerequisites.

Guidelines and Limitations for Keychain Management

Keychain management has the following configuration guideline and limitation:

  • Changing the system clock impacts when the keys are active.

Default Settings for Keychain Management

This table lists the default settings for Cisco NX-OS keychain management parameters.



Table 1 Default Keychain Management Parameters

Parameters

Default

Key chains

No keychain exists by default.

Keys

No keys are created by default when you create a new keychain.

Accept lifetime

Always valid.

Send lifetime

Always valid.

Key-string entry encryption

Unencrypted.

Configuring Keychain Management

Creating a Keychain

You can create a keychain on the device. A new keychain contains no keys.

SUMMARY STEPS

    1.    configure terminal

    2.    key chain name

    3.    (Optional) show key chain name

    4.    (Optional) copy running-config startup-config


DETAILED STEPS
     Command or ActionPurpose
    Step 1 configure terminal


    Example: 
    switch# configure terminal
switch(config)#
     

    Enters global configuration mode.

     
    Step 2 key chain name


    Example: 
    switch(config)# key chain glbp-keys
switch(config-keychain)#
     

    Creates the keychain and enters keychain configuration mode.

     
    Step 3 show key chain name


    Example: 
    switch(config-keychain)# show key chain glbp-keys
          		(Optional)

    Displays the keychain configuration.

     
    Step 4 copy running-config startup-config


    Example: 
    switch(config-keychain)# copy running-config startup-config
          		(Optional)

    Copies the running configuration to the startup configuration.

     

    Removing a Keychain

    You can remove a keychain on the device.


    Note

    Removing a keychain removes any keys within the keychain.

    Before You Begin

    If you are removing a keychain, ensure that no feature uses it. If a feature is configured to use a keychain that you remove, that feature is likely to fail to communicate with other devices.

    SUMMARY STEPS

      1.    configure terminal

      2.    no key chain name

      3.    (Optional) show key chain name

      4.    (Optional) copy running-config startup-config


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 configure terminal


      Example: 
      switch# configure terminal
switch(config)#
       

      Enters global configuration mode.

       
      Step 2 no key chain name


      Example: 
      switch(config)# no key chain glbp-keys
       

      Removes the keychain and any keys that the keychain contains.

       
      Step 3 show key chain name


      Example: 
      switch(config-keychain)# show key chain glbp-keys
              		(Optional)

      Confirms that the keychain no longer exists in running configuration.

       
      Step 4 copy running-config startup-config


      Example: 
      switch(config-keychain)# copy running-config startup-config
              		(Optional)

      Copies the running configuration to the startup configuration.

       

      Configuring a Master Key and Enabling the AES Password Encryption Feature

      You can configure a master key for type-6 encryption and enable the Advanced Encryption Standard (AES) password encryption feature.

      SUMMARY STEPS

        1.    [no] key config-key ascii

        2.    configure terminal

        3.    [no] feature password encryption aes

        4.    (Optional) show encryption service stat

        5.    copy running-config startup-config


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 [no] key config-key ascii


        Example: 
        switch# key config-key ascii
New Master Key:
Retype Master Key:
         

        Configures a master key to be used with the AES password encryption feature. The master key can contain between 16 and 32 alphanumeric characters. You can use the no form of this command to delete the master key at any time.

        If you enable the AES password encryption feature before configuring a master key, a message appears stating that password encryption will not take place unless a master key is configured. If a master key is already configured, you are prompted to enter the current master key before entering a new master key.

         
        Step 2 configure terminal


        Example: 
        switch# configure terminal
switch(config)#
         

        Enters global configuration mode.

         
        Step 3 [no] feature password encryption aes


        Example: 
        switch(config)# feature password encryption aes
         

        Enables or disables the AES password encryption feature.

         
        Step 4 show encryption service stat


        Example: 
        switch(config)# show encryption service stat
                  		(Optional)

        Displays the configuration status of the AES password encryption feature and the master key.

         
        Step 5 copy running-config startup-config


        Example: 
        switch(config)# copy running-config startup-config
         

        Copies the running configuration to the startup configuration.

        Note   

        This command is necessary to synchronize the master key in the running configuration and the startup configuration.

         

        Configuring Text for a Key

        You can configure the text for a key. The text is the shared secret. The device stores the text in a secure format.

        By default, accept and send lifetimes for a key are infinite, which means that the key is always valid. After you configure the text for a key, configure the accept and send lifetimes for the key.

        Before You Begin

        Determine the text for the key. You can enter the text as unencrypted text or in the encrypted form that Cisco NX-OS uses to display key text when you use the show key chain command. Using the encrypted form is particularly helpful if you are creating key text to match a key as shown in the show key chain command output from another device.

        SUMMARY STEPS

          1.    configure terminal

          2.    key chain name

          3.    key key-ID

          4.    key-string [encryption-type] text-string

          5.    (Optional) show key chain name [mode decrypt]

          6.    (Optional) copy running-config startup-config


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 configure terminal


          Example: 
          switch# configure terminal
switch(config)#
           

          Enters global configuration mode.

           
          Step 2 key chain name


          Example: 
          switch(config)# key chain glbp-keys
switch(config-keychain)#
           

          Enters keychain configuration mode for the keychain that you specified.

           
          Step 3 key key-ID


          Example: 
          switch(config-keychain)# key 13
switch(config-keychain-key)#
           

          Enters key configuration mode for the key that you specified. The key-ID argument must be a whole number between 0 and 65535.

           
          Step 4 key-string [encryption-type] text-string


          Example: 
          switch(config-keychain-key)# key-string 0 AS3cureStr1ng
           

          Configures the text string for the key. The text-string argument is alphanumeric, case-sensitive, and supports special characters.

          The encryption-type argument can be one of the following values:

          • 0—The text-string argument that you enter is unencrypted text. This is the default.
          • 7—The text-string argument that you enter is encrypted. The encryption method is a Cisco proprietary method. This option is useful when you are entering a text string based on the encrypted output of a show key chain command that you ran on another Cisco NX-OS device.
           
          Step 5 show key chain name [mode decrypt]


          Example: 
          switch(config-keychain-key)# show key chain glbp-keys
                      		(Optional)

          Shows the keychain configuration, including the key text configuration. The mode decrypt option, which can be used by a device administrator only, displays the keys in cleartext.

           
          Step 6 copy running-config startup-config


          Example: 
          switch(config-keychain-key)# copy running-config startup-config
                      		(Optional)

          Copies the running configuration to the startup configuration.

           

          Configuring Accept and Send Lifetimes for a Key

          You can configure the accept lifetime and send lifetime for a key. By default, accept and send lifetimes for a key are infinite, which means that the key is always valid.


          Note

          We recommend that you configure the keys in a keychain to have overlapping lifetimes. This practice prevents loss of key-secured communication due to moments where no key is active.

          SUMMARY STEPS

            1.    configure terminal

            2.    key chain name

            3.    key key-ID

            4.    accept-lifetime [local] start-time duration duration-value | infinite | end-time]

            5.    send-lifetime [local] start-time duration duration-value | infinite | end-time]

            6.    (Optional) show key chain name [mode decrypt]

            7.    (Optional) copy running-config startup-config


          DETAILED STEPS
             Command or ActionPurpose
            Step 1 configure terminal


            Example: 
            switch# configure terminal
switch(config)#
             

            Enters global configuration mode.

             
            Step 2 key chain name


            Example: 
            switch(config)# key chain glbp-keys
switch(config-keychain)#
             

            Enters keychain configuration mode for the keychain that you specified.

             
            Step 3 key key-ID


            Example: 
            switch(config-keychain)# key 13
switch(config-keychain-key)#
             

            Enters key configuration mode for the key that you specified.

             
            Step 4 accept-lifetime [local] start-time duration duration-value | infinite | end-time]


            Example: 
            switch(config-keychain-key)# accept-lifetime 00:00:00 Jun 13 2008 23:59:59 Sep 12 2008
             

            Configures an accept lifetime for the key. By default, the device treats the start-time and end-time arguments as UTC. If you specify the local keyword, the device treats these times as local times.

            The start-time argument is the time of day and date that the key becomes active.

            Specify the end of the lifetime with one of the following options:

            • duration duration-value —The length of the lifetime in seconds. The maximum length is 2147483646 seconds (approximately 68 years).
            • infinite—The accept lifetime of the key never expires.
            • end-time —The end-time argument is the time of day and date that the key becomes inactive.
             
            Step 5 send-lifetime [local] start-time duration duration-value | infinite | end-time]


            Example: 
            switch(config-keychain-key)# send-lifetime 00:00:00 Jun 13 2008 23:59:59 Aug 12 2008
             

            Configures a send lifetime for the key. By default, the device treats the start-time and end-time arguments as UTC. If you specify the local keyword, the device treats these times as local times.

            The start-time argument is the time of day and date that the key becomes active.

            You can specify the end of the send lifetime with one of the following options:

            • duration duration-value —The length of the lifetime in seconds. The maximum length is 2147483646 seconds (approximately 68 years).
            • infinite—The send lifetime of the key never expires.
            • end-time —The end-time argument is the time of day and date that the key becomes inactive.
             
            Step 6 show key chain name [mode decrypt]


            Example: 
            switch(config-keychain-key)# show key chain glbp-keys
                          		(Optional)

            Shows the keychain configuration, including the key text configuration. The mode decrypt option, which can be used by a device administrator only, displays the keys in cleartext.

             
            Step 7 copy running-config startup-config


            Example: 
            switch(config-keychain-key)# copy running-config startup-config
                          		(Optional)

            Copies the running configuration to the startup configuration.

             

            Determining Active Key Lifetimes

            To determine which keys within a keychain have active accept or send lifetimes, use the command in this table. For detailed information about the fields in the output from this command, see the Cisco Nexus 7000 Series NX-OS Security Command Reference.

            Command

            Purpose

            show key chain

            Displays the keychains configured on the device.

            Verifying the Keychain Management Configuration

            To display keychain management configuration information, perform the following task. For detailed information about the fields in the output from this command, see the Cisco Nexus 7000 Series NX-OS Security Command Reference.

            Command

            Purpose

            show key chain

            Displays the keychains configured on the device.

            Configuration Example for Keychain Management

            This example shows how to configure a keychain named glbp keys. Each key text string is encrypted. Each key has longer accept lifetimes than send lifetimes, to help prevent lost communications by accidentally configuring a time in which there are no active keys.

            key chain glbp-keys
  key 0
    key-string 7 zqdest
    accept-lifetime 00:00:00 Jun 01 2008 23:59:59 Sep 12 2008
    send-lifetime 00:00:00 Jun 01 2008 23:59:59 Aug 12 2008
  key 1
    key-string 7 uaeqdyito
    accept-lifetime 00:00:00 Aug 12 2008 23:59:59 Dec 12 2008
    send-lifetime 00:00:00 Sep 12 2008 23:59:59 Nov 12 2008
  key 2
    key-string 7 eekgsdyd
    accept-lifetime 00:00:00 Nov 12 2008 23:59:59 Mar 12 2009
    send-lifetime 00:00:00 Dec 12 2008 23:59:59 Feb 12 2009

            Where to Go Next

            For information about routing features that use keychains, see the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide.

            Additional References for Keychain Management

            Related Documents

            Related Topic

            Document Title

            Gateway Load Balancing Protocol

            Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide

            Border Gateway Protocol

            Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide

            Keychain management commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

            Cisco Nexus 7000 Series NX-OS Security Command Reference

            Standards

            Standards

            Title

            No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

            —

            Feature History for Keychain Management

            This table lists the release history for this feature.

            Table 2 Feature History for Keychain Management

            Feature Name

            Releases

            Feature Information

            Keychain management

            6.0(1)

            No change from Release 5.2.

            Keychain management

            5.2(1)

            No change from Release 5.1.

            Keychain management

            5.1(1)

            No change from Release 5.0.

            Keychain management

            5.0(2)

            No change from Release 4.2.

            Keychain management

            4.2(1)

            No change from Release 4.1.