Secure Shell Configuration Guide Cisco IOS XE Release 3S
Secure Copy
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Secure Copy

Secure Copy

The Secure Copy (SCP) feature provides a secure and authenticated method for copying router configuration or router image files. SCP relies on Secure Shell (SSH), an application and a protocol that provide a secure replacement for the Berkeley r-tools.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

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.

Prerequisites for Secure Copy

  • Before enabling SCP, you must correctly configure SSH, authentication, and authorization on the router.
  • Because SCP relies on SSH for its secure transport, the router must have an Rivest, Shamir, and Adelman (RSA) key pair.

Information About Secure Copy

How SCP Works

The behavior of SCP is similar to that of remote copy (rcp), which comes from the Berkeley r-tools suite, except that SCP relies on SSH for security. In addition, SCP requires that authentication, authorization, and accounting (AAA) authorization be configured so the router can determine whether the user has the correct privilege level.

SCP allows a user who has appropriate authorization to copy any file that exists in the Cisco IOS XE File System (IFS) to and from a router by using the copy command. An authorized administrator may also perform this action from a workstation.

How to Configure SCP

Configuring SCP

To enable and configure a Cisco router for SCP server-side functionality, perform the following steps.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    aaa new-model

    4.    aaa authentication login {default | list-name} method1[method2...]

    5.    aaa authorization {network | exec | commands level | reverse-access | configuration} {default | list-name} [method1 [method2...]]

    6.    username name [privilege level]{password encryption-type encrypted-password}

    7.    ip scp server enable


DETAILED STEPS
      Command or Action Purpose
    Step 1 enable


    Example:
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 aaa new-model


    Example:
    Router (config)# aaa new-model
     

    Sets AAA authentication at login.

     
    Step 4 aaa authentication login {default | list-name} method1[method2...]


    Example:
    Router (config)# aaa authentication login default group tacacs+
     

    Enables the AAA access control system.

     
    Step 5 aaa authorization {network | exec | commands level | reverse-access | configuration} {default | list-name} [method1 [method2...]]


    Example:
    Router (config)# aaa authorization exec default group tacacs+
     

    Sets parameters that restrict user access to a network.

    Note   

    The exec keyword runs authorization to determine if the user is allowed to run an EXEC shell; therefore, you must use it when you configure SCP.

     
    Step 6 username name [privilege level]{password encryption-type encrypted-password}


    Example:
    Router (config)# username superuser privilege 2 password 0 superpassword
     

    Establishes a username-based authentication system.

    Note   

    You may skip this step if a network-based authentication mechanism--such as TACACS+ or RADIUS--has been configured.

     
    Step 7 ip scp server enable


    Example:
    Router (config)# ip scp server enable
     

    Enables SCP server-side functionality.

     

    Verifying SCP

    To verify SCP server-side functionality, perform the following steps.

    SUMMARY STEPS

      1.    enable

      2.    show running-config


    DETAILED STEPS
        Command or Action Purpose
      Step 1 enable


      Example:
      Router> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 show running-config


      Example:
      Router# show running-config
       

      Verifies the SCP server-side functionality.

       

      Troubleshooting SCP

      SUMMARY STEPS

        1.    enable

        2.    debug ip scp


      DETAILED STEPS
          Command or Action Purpose
        Step 1 enable


        Example:
        Router> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 debug ip scp


        Example:
        Router# debug ip scp
         

        Troubleshoots SCP authentication problems.

         

        Configuration Examples for Secure Copy

        Example SCP Server-Side Configuration Using Local Authentication

        The following example shows how to configure the server-side functionality of SCP. This example uses a locally defined username and password.

        ! AAA authentication and authorization must be configured properly for SCP to work.
        aaa new-model
        aaa authentication login default local
        aaa authorization exec default local
        username tiger privilege 15 password 0 lab
        ! SSH must be configured and functioning properly.
        ip ssh time-out 120
        ip ssh authentication-retries 3
        ip scp server enable

        Example SCP Server-Side Configuration Using Network-Based Authentication

        The following example shows how to configure the server-side functionality of SCP using a network-based authentication mechanism:

        ! AAA authentication and authorization must be configured properly for SCP to work. 
        aaa new-model 
        aaa authentication login default group tacacs+
        aaa authorization exec default group tacacs+
        ! SSH must be configured and functioning properly.
        ip ssh time-out 120
        ip ssh authentication-retries 3
        ip scp server enable

        Additional References

        Related Documents

        Related Topic

        Document Title

        Cisco IOS commands

        Cisco IOS Master Commands List, All Releases

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

        Cisco IOS Security Command Reference

        Secure Shell

        Configuring Secure Shell and Secure Shell Version 2 Support feature modules.

        Configuring authentication and authorization

        Configuring Authentication , Configuring Authorization , and Configuring Accounting feature modules.

        Standards

        Standards

        Title

        None

        --

        MIBs

        MIBs

        MIBs Link

        None

        To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

        http:/​/​www.cisco.com/​go/​mibs

        RFCs

        RFCs

        Title

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

        --

        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 Secure Copy

        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 Secure Copy

        Feature Name

        Releases

        Feature Configuration Information

        Secure Copy

        Cisco IOS XE Release 2.1

        The Secure Copy (SCP) feature provides a secure and authenticated method for copying router configuration or router image files. SCP relies on Secure Shell (SSH), an application and a protocol that provide a secure replacement for the Berkeley r-tools.

        In Cisco IOS XE Release 2.1, this feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers.

        The following commands were introduced or modified: debug ip scp, ip scp server enable.

        Glossary

        AAA --authentication, authorization, and accounting. Framework of security services that provide the method for identifying users (authentication), for remote access control (authorization), and for collecting and sending security server information used for billing, auditing, and reporting (accounting).

        rcp --remote copy. Relying on Remote Shell (Berkeley r-tools suite) for security, rcp copies files, such as router images and startup configurations, to and from routers.

        SCP --secure copy. Relying on SSH for security, SCP support allows the secure and authenticated copying of anything that exists in the Cisco IOS XE File Systems. SCP is derived from rcp.

        SSH --Secure Shell. Application and a protocol that provide a secure replacement for the Berkeley r-tools. The protocol secures the sessions using standard cryptographic mechanisms, and the application can be used similarly to the Berkeley rexec and rsh tools. SSH Version 1 is implemented in the Cisco IOS XE software.