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The Secure Copy Protocol (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.
From Cisco IOS XE Everest 16.6.1 release, the SCP feature has been enhanced to provide user access to configure the SSH/SCP window-size, thus improving the speed and performance of the SCP operation.
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.
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.
To overcome the problem of SCP performance degradation, an option to increase the window-size used for SSH/SCP is supported. Depending on the window-size internally, the buffer size is adjusted to improve the bandwidth utilization. Normal SSH/SCP operation is not impacted due to the changes, as the existing default values are the same.
To enable and configure a Cisco router for SCP server-side functionality, perform the following 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
To acess and modify the SCP window-size, perform the following steps.
1.
enable
2.
configure
terminal
3.
ip
ssh
window-size
bytes
4.
exit
Command or Action | Purpose | |||||
---|---|---|---|---|---|---|
Step 1 |
enable
Example: Device> enable |
Enables privileged EXEC mode.
| ||||
Step 2 |
configure
terminal
Example: Device# configure termminal |
Enters global configuration mode. | ||||
Step 3 |
ip
ssh
window-size
bytes
Example: Device(config)# ip ssh window-size 65536 |
Modifies the SCP window-size. The range (in bytes) is from 8192 to 131072.
| ||||
Step 4 |
exit
Example: Device(config)# exit |
Exits to privileged EXEC mode. |
To verify SCP server-side functionality, perform the following steps.
1.
enable
2.
show
running-config
Command or Action | Purpose |
---|
1.
enable
2.
debug
ip
scp
Command or Action | Purpose |
---|
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
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
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
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 |
Title |
---|---|
None |
-- |
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: |
RFCs |
Title |
---|---|
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
-- |
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. |
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.
Feature Name |
Releases |
Feature Configuration Information |
---|---|---|
SCP Performance Improvement |
Cisco IOS XE Everest Release 16.6.1 |
The Secure Copy Protocol (SCP) Performance Improvement feature provides user access to configure the SSH/SCP window-size, thus improving the speed and performance of the SCP operation. The following commands were introduced or modified: ip ssh window-size bytes. |
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. |
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.