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Cisco IOS Software Releases 12.2 T

Secure Copy

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Secure Copy

Contents

Prerequisites for Secure Copy

Information About Secure Copy

How SCP Works

How to Configure SCP

Configuring SCP

Verifying SCP

Troubleshooting SCP

Configuration Examples for Secure Copy

SCP Server-Side Configuration Using Local Authentication: Example

SCP Server-Side Configuration Using Network-Based Authentication: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

debug ip scp

ip scp server enable

Glossary


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.

Feature History for Secure Copy

Release
Modification

12.2(2)T

This feature was introduced.

12.0(21)S

This feature was integrated into Cisco IOS 12.0(21)S.

12.2(25)S

This feature was integrated into Cisco IOS 12.2(25)S.


Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

•Prerequisites for Secure Copy

•Information About Secure Copy

•How to Configure SCP

•Configuration Examples for Secure Copy

•Additional References

•Command Reference

•Glossary

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

To configure Secure Copy feature, you should understand the following concepts.

•How SCP Works

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 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

This section contains the following procedures:

•Configuring SCP

•Verifying SCP

•Troubleshooting 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
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

To troubleshoot SCP authentication problems, perform the following steps.

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

This section provides the following configuration examples:

•SCP Server-Side Configuration Using Local Authentication: Example

•SCP Server-Side Configuration Using Network-Based Authentication: Example

SCP Server-Side Configuration Using Local Authentication: Example

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

SCP Server-Side Configuration Using Network-Based Authentication: Example

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

The following sections provide references related to Secure Copy.

Related Documents

Related Topic
Document Title

Secure Shell

•Secure Shell Version 1 Support

•Secure Shell Version 2 Support

Authentication and authorization commands

Cisco IOS Security Command Reference, Release 12.3 T

Configuring authentication and authorization

"Authentication, Authorization, and Accounting (AAA)" section of Cisco IOS Security Configuration Guide, Release 12.3


Standards

Standards
Title

No new or modified standards are supported by this feature.

—


MIBs

MIBs
MIBs Link

No new or modified MIBs are supported by this feature.

To locate and download MIBs for selected platforms, Cisco IOS 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.

—


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml


Command Reference

This section documents only new commands.

•debug ip scp

•ip scp server enable

debug ip scp

To troubleshooot secure copy (SCP) authentication problems, use the debug ip scp command in privileged EXEC mode. To disable debugging output, use the no form of this command.

debug ip scp

no debug ip scp

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)S

This command was integrated into Cisco IOS Release 12.0(21)S.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S.


Examples

The following example is sample output from the debug ip scp command. In this example, a copy of the file scptest.cfg from a UNIX host running configuration of the router was successful. 

Router# debug ip scp


4d06h:SCP:[22 -> 10.11.29.252:1018] send <OK>

4d06h:SCP:[22 <- 10.11.29.252:1018] recv C0644 20 scptest.cfg

4d06h:SCP:[22 -> 10.11.29.252:1018] send <OK>

4d06h:SCP:[22 <- 10.11.29.252:1018] recv 20 bytes

4d06h:SCP:[22 <- 10.11.29.252:1018] recv <OK>

4d06h:SCP:[22 -> 10.11.29.252:1018] send <OK>

4d06h:SCP:[22 <- 10.11.29.252:1018] recv <EOF>

The following example is also sample output from the debug ip scp command, but in this example, the user has privilege 0 and is therefore denied: 

Router# debug ip scp


4d06h:SCP:[22 -> 10.11.29.252:1018] send Privilege denied.

Related Commands

Command
Description

ip scp server enable

Enables SCP server-side functionality.


ip scp server enable

To enable secure copy (SCP) server-side functionality, use the ip scp server enable command in global configuration mode. To disable this functionality, use the no form of this command.

ip scp server enable

no ip scp server enable

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)S

This command was integrated into Cisco IOS Release 12.0(21)S.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S.


Usage Guidelines

Use the ip scp server enable command to enable a Cisco router to support SCP server-side functionality, which allows an authenticated user to securely copy configuration and image files to or from a remote workstation.

Before a user can utilize the SCP server-side functionality, Secure Shell (SSH), authentication, and authorization must be properly configured so a router can determine whether a user is at the correct privilege level.

Examples

The following example shows how to transfer a file from the router using SCP: 

Router# copy flash:c3620-ik9s-mz.122-0.17.T scp://tiger@10.1.1.2/ 

Address or name of remote host [10.1.1.2]? 

Destination username [tiger]? 

Destination filename [c3620-ik9s-mz.122-0.17.T]? 

Writing c3620-ik9s-mz.122-0.17.T 

Password: 


Router#

Note When using SCP, you cannot enter the password into the copy command. You must enter the password when prompted.

Related Commands

Command
Description

aaa authentication login

Sets AAA authentication at login.

aaa authorization

Sets parameters that restrict user access to a network.

copy

Copies any file from a source to a destination.

username

Establishes a username-based authentication system.


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 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 software.

Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.

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