Cisco Nexus 3600 NX-OS User manual

Cisco Nexus 3600 NX-OS Security Configuration Guide, Release 7.x
First Published: 2017-09-27
Last Modified: 2018-02-27
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CONTENTS
Preface Preface xi
Audience xi
Document Conventions xi
Obtaining Documentation and Submitting a Service Request xii
Documentation Feedback xii
Related Documentation for Cisco Nexus 3600 Platform Switches xiii
CHAPTER 1 New and Changed Information 1
New and Changed Information 1
CHAPTER 2 Overview 3
Authentication, Authorization, and Accounting 3
RADIUS and TACACS+ Security Protocols 4
SSH and Telnet 4
SSH and Telnet 5
IP ACLs 5
CHAPTER 3 Configuring AAA 7
Information About AAA 7
AAA Security Services 7
Benefits of Using AAA 8
Remote AAA Services 8
AAA Server Groups 8
AAA Service Configuration Options 9
Authentication and Authorization Process for User Logins 10
Prerequisites for Remote AAA 11
Guidelines and Limitations for AAA 12
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Configuring AAA 12
Configuring Console Login Authentication Methods 12
Configuring Default Login Authentication Methods 13
Enabling Login Authentication Failure Messages 14
Logging Successful and Failed Login Attempts 15
Configuring AAA Command Authorization 16
Enabling MSCHAP Authentication 17
Configuring AAA Accounting Default Methods 18
Using AAA Server VSAs 20
VSAs 20
VSA Format 20
Specifying Switch User Roles and SNMPv3 Parameters on AAA Servers 20
Secure Login Enhancements 21
Secure Login Enhancements 21
Configuring Login Parameters 21
Configuration Examples for Login Parameters 22
Restricting Sessions Per User—Per User Per Login 23
Enabling the Password Prompt for User Name 24
Configuring Share Key Value for using RADIUS/TACACS+ 24
Monitoring and Clearing the Local AAA Accounting Log 25
Verifying the AAA Configuration 25
Configuration Examples for AAA 26
Default AAA Settings 26
CHAPTER 4 Configuring RADIUS 29
Information About RADIUS 29
RADIUS Network Environments 29
Information About RADIUS Operations 30
RADIUS Server Monitoring 31
Vendor-Specific Attributes 31
Prerequisites for RADIUS 32
Guidelines and Limitations for RADIUS 32
Configuring RADIUS Servers 32
Configuring RADIUS Server Hosts 33
Configuring RADIUS Global Preshared Keys 34
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Configuring RADIUS Server Preshared Keys 34
Configuring RADIUS Server Groups 35
Configuring the Global Source Interface for RADIUS Server Groups 37
Allowing Users to Specify a RADIUS Server at Login 37
Configuring the Global RADIUS Transmission Retry Count and Timeout Interval 38
Configuring Accounting and Authentication Attributes for RADIUS Servers 39
Configuring Periodic RADIUS Server Monitoring 40
Configuring the Dead-Time Interval 41
Manually Monitoring RADIUS Servers or Groups 42
Verifying the RADIUS Configuration 43
Displaying RADIUS Server Statistics 43
Clearing RADIUS Server Statistics 43
Configuration Examples for RADIUS 44
Default Settings for RADIUS 44
Feature History for RADIUS 44
CHAPTER 5 Configuring TACACS+ 45
Information About Configuring TACACS+ 45
TACACS+ Advantages 45
User Login with TACACS+ 46
Default TACACS+ Server Encryption Type and Preshared Key 46
TACACS+ Server Monitoring 47
Prerequisites for TACACS+ 47
Guidelines and Limitations for TACACS+ 48
Configuring TACACS+ 48
TACACS+ Server Configuration Process 48
Enabling TACACS+ 48
Configuring TACACS+ Server Hosts 49
Configuring TACACS+ Global Preshared Keys 50
Configuring TACACS+ Server Groups 51
Configuring the Global Source Interface for TACACS+ Server Groups 52
Configuring the Global TACACS+ Timeout Interval 52
Configuring the Timeout Interval for a Server 53
Configuring TCP Ports 53
Configuring Periodic TACACS+ Server Monitoring 54
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Configuring the Dead-Time Interval 55
Manually Monitoring TACACS+ Servers or Groups 56
Disabling TACACS+ 56
Displaying TACACS+ Statistics 57
Verifying the TACACS+ Configuration 57
Configuration Examples for TACACS+ 57
Default Settings for TACACS+ 58
CHAPTER 6 Configuring SSH and Telnet 59
Information About SSH and Telnet 59
SSH Server 59
SSH Client 59
SSH Server Keys 60
SSH Authentication Using Digital Certificates 60
Telnet Server 61
Guidelines and Limitations for SSH 61
Configuring SSH 61
Generating SSH Server Keys 61
Specifying the SSH Public Keys for User Accounts 62
Specifying the SSH Public Keys in Open SSH Format 62
Specifying the SSH Public Keys in IETF SECSH Format 63
Specifying the SSH Public Keys in PEM-Formatted Public Key Certificate Form 63
Configuring the SSH Source Interface 64
Starting SSH Sessions to Remote Devices 65
Clearing SSH Hosts 65
Disabling the SSH Server 65
Deleting SSH Server Keys 66
Clearing SSH Sessions 66
Configuration Examples for SSH 67
Configuring X.509v3 Certificate-Based SSH Authentication 68
Configuration Example for X.509v3 Certificate-Based SSH Authentication 70
Configuring Telnet 71
Enabling the Telnet Server 71
Reenabling the Telnet Server 71
Configuring the Telnet Source Interface 71
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Starting Telnet Sessions to Remote Devices 72
Clearing Telnet Sessions 72
Verifying the SSH and Telnet Configuration 73
Default Settings for SSH 73
CHAPTER 7 Configuring IP ACLs 75
Information About ACLs 75
IP ACL Types and Applications 76
Application Order 76
Rules 76
Source and Destination 77
Protocols 77
Implicit Rules 77
Additional Filtering Options 77
Sequence Numbers 77
Logical Operators and Logical Operation Units 78
ACL TCAM Regions 78
Licensing Requirements for ACLs 79
Prerequisites for ACLs 79
Guidelines and Limitations for ACLs 80
Default ACL Settings 80
ACL Logging 81
Configuring IP ACLs 81
Creating an IP ACL 81
Configuring IPv4 ACL Logging 82
Changing an IP ACL 84
Removing an IP ACL 85
Changing Sequence Numbers in an IP ACL 86
Applying an IP ACL to mgmt0 86
Applying an IP ACL as a Port ACL 87
Applying an IP ACL as a Router ACL 87
Verifying the ACL Logging Configuration 88
About System ACLs 89
Carving a TCAM Region 90
Configuring System ACLs 90
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Configuration and Show Command Examples for the System ACLs 90
Configuring ACL Logging 92
Configuring the ACL Logging Cache 92
Applying ACL Logging to an Interface 93
Applying the ACL Log Match Level 94
Clearing Log Files 94
Verifying the ACL Logging Configuration 94
Configuring ACL TCAM Region Sizes 95
Reverting to the Default TCAM Region Sizes 97
Configuring ACLs on Virtual Terminal Lines 97
Verifying ACLs on VTY Lines 99
Configuration Examples for ACLs on VTY Lines 99
CHAPTER 8 Configuring Unicast RPF 101
Information About Unicast RPF 101
Unicast RPF Process 102
Global Statistics 102
Licensing Requirements for Unicast RPF 103
Guidelines and Limitations for Unicast RPF 103
Default Settings for Unicast RPF 104
Configuring Unicast RPF 104
Configuration Examples for Unicast RPF 106
Verifying the Unicast RPF Configuration 106
Additional References for Unicast RPF 107
CHAPTER 9 Configuring Control Plane Policing 109
About CoPP 109
Control Plane Protection 110
Control Plane Packet Types 111
Classification for CoPP 111
Rate Controlling Mechanisms 112
Dynamic and Static CoPP ACLs 112
Default Policing Policies 113
Default Class Maps - For Cisco NX-OS Release 7.0(3)I3(1) 114
Strict Default CoPP Policy - For Cisco NX-OS Release 7.0(3)I3(1) 116
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Moderate Default CoPP Policy - For Cisco NX-OS Release 7.0(3)I3(1) 118
Lenient Default CoPP Policy - For Cisco NX-OS Release 7.0(3)I3(1) 120
Dense Default CoPP Policy - For Cisco NX-OS Release 7.0(3)I3(1) 122
Packets Per Second Credit Limit 124
Modular QoS Command-Line Interface 124
CoPP and the Management Interface 124
Licensing Requirements for CoPP 125
Guidelines and Limitations for CoPP 125
Default Settings for CoPP 127
Configuring CoPP 127
Configuring a Control Plane Class Map 127
Configuring a Control Plane Policy Map 129
Configuring the Control Plane Service Policy 131
Configuring the CoPP Scale Factor Per Line Card 132
Changing or Reapplying the Default CoPP Policy 133
Copying the CoPP Best Practice Policy 134
Verifying the CoPP Configuration 135
Displaying the CoPP Configuration Status 137
Monitoring CoPP 137
Clearing the CoPP Statistics 138
Configuration Examples for CoPP 138
CoPP Configuration Example 138
Changing or Reapplying the Default CoPP Policy Using the Setup Utility 139
Additional References for CoPP 140
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Contents

Preface
This preface includes the following sections:
•Audience, page xi
•Document Conventions, page xi
•Obtaining Documentation and Submitting a Service Request, page xii
•Documentation Feedback, page xii
•Related Documentation for Cisco Nexus 3600 Platform Switches, page xiii
Audience
This publication is for network administrators who install, configure, and maintain Cisco Nexus switches.
Document Conventions
Command descriptions use the following conventions:
DescriptionConvention
Bold text indicates the commands and keywords that you enter literally
as shown.
bold
Italic text indicates arguments for which the user supplies the values.
Italic
Square brackets enclose an optional element (keyword or argument).[x]
Square brackets enclosing keywords or arguments separated by a vertical
bar indicate an optional choice.
[x | y]
Braces enclosing keywords or arguments separated by a vertical bar
indicate a required choice.
{x | y}
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DescriptionConvention
Nested set of square brackets or braces indicate optional or required
choices within optional or required elements. Braces and a vertical bar
within square brackets indicate a required choice within an optional
element.
[x {y | z}]
Indicates a variable for which you supply values, in context where italics
cannot be used.
variable
A nonquoted set of characters. Do not use quotation marks around the
string or the string will include the quotation marks.
string
Examples use the following conventions:
DescriptionConvention
Terminal sessions and information the switch displays are in screen font.screen font
Information you must enter is in boldface screen font.boldface screen font
Arguments for which you supply values are in italic screen font.
italic screen font
Nonprinting characters, such as passwords, are in angle brackets.< >
Default responses to system prompts are in square brackets.[ ]
An exclamation point (!) or a pound sign (#) at the beginning of a line
of code indicates a comment line.
!, #
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, using the Cisco Bug Search Tool (BST), submitting a service
request, and gathering additional information, see What's New in Cisco Product Documentation at: http://
www.cisco.com/c/en/us/td/docs/general/whatsnew/whatsnew.html.
Subscribe to What's New in Cisco Product Documentation, which lists all new and revised Cisco technical
documentation as an RSS feed and delivers content directly to your desktop using a reader application. The
RSS feeds are a free service.
Documentation Feedback
To provide technical feedback on this document, or to report an error or omission, please send your comments
to [email protected]. We appreciate your feedback.
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Preface
Obtaining Documentation and Submitting a Service Request

RelatedDocumentationforCiscoNexus3600PlatformSwitches
The entire Cisco Nexus 3600 platform switch documentation set is available at the following URL:
http://www.cisco.com/c/en/us/support/switches/nexus-3000-series-switches/
tsd-products-support-series-home.html
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Preface
Related Documentation for Cisco Nexus 3600 Platform Switches

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Preface
Related Documentation for Cisco Nexus 3600 Platform Switches

CHAPTER 1
New and Changed Information
This chapter provides release-specific information for each new and changed feature in the Cisco Nexus
3600 Series NX-OS Security Configuration Guide.
•New and Changed Information, page 1
New and Changed Information
This table summarizes the new and changed features for the Cisco Nexus 3600 Series NX-OS Security
Configuration Guide and where they are documented.
Table 1: New and Changed Features
Where DocumentedChanged
in
Release
DescriptionFeature
About System ACLs, on page
89
7.0(3)F3(4)Added support for configuring
system ACLs.
System ACLs
Configuring IP ACLs, on page
75
7.0(3)F3(1)Added support for Access
Control Lists (ACLs).
Access Control Lists
Configuring AAA, on page 77.0(3)F3(1)Added support for
Authentication, Authorization,
and Accounting (AAA).
Authentication, Authorization,
and Accounting
Configuring SSH and Telnet,
on page 59
7.0(3)F3(1)Added support for SSH and
Telnet.
SSH and Telnet
Configuring TACACS+, on
page 45
7.0(3)F3(1)Added support for TACACS+.TACACS+
Configuring RADIUS, on page
29
7.0(3)F3(1)Added support for RADIUS.RADIUS
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Where DocumentedChanged
in
Release
DescriptionFeature
Configuring Unicast RPF, on
page 101
7.0(3)F3(1)Added support for unicast RPF.Unicast RPF
Configuring Control Plane
Policing, on page 109
7.0(3)F3(1)Added support for CoPPControl Plane Policing (CoPP)
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New and Changed Information
New and Changed Information

CHAPTER 2
Overview
The Cisco NX-OS software supports security features that can protect your network against degradation or
failure and also against data loss or compromise resulting from intentional attacks and from unintended but
damaging mistakes by well-meaning network users.
•Authentication, Authorization, and Accounting, page 3
•RADIUS and TACACS+ Security Protocols, page 4
•SSH and Telnet, page 4
•SSH and Telnet, page 5
•IP ACLs, page 5
Authentication, Authorization, and Accounting
Authentication, authorization, and accounting (AAA) is an architectural framework for configuring a set of
three independent security functions in a consistent, modular manner.
Authentication
Provides the method of identifying users, including login and password dialog, challenge and response,
messaging support, and, depending on the security protocol that you select, encryption. Authentication
is the way a user is identified prior to being allowed access to the network and network services. You
configure AAA authentication by defining a named list of authentication methods and then applying
that list to various interfaces.
Authorization
Provides the method for remote access control, including one-time authorization or authorization for
each service, per-user account list and profile, user group support, and support of IP, IPX, ARA, and
Telnet.
Remote security servers, such as RADIUS and TACACS+, authorize users for specific rights by
associating attribute-value (AV) pairs, which define those rights, with the appropriate user. AAA
authorization works by assembling a set of attributes that describe what the user is authorized to perform.
These attributes are compared with the information contained in a database for a given user, and the
result is returned to AAA to determine the user’s actual capabilities and restrictions.
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Accounting
Provides the method for collecting and sending security server information used for billing, auditing,
and reporting, such as user identities, start and stop times, executed commands (such as PPP), number
of packets, and number of bytes. Accounting enables you to track the services that users are accessing,
as well as the amount of network resources that they are consuming.
You can configure authentication outside of AAA. However, you must configure AAA if you want to use
RADIUS or TACACS+, or if you want to configure a backup authentication method.
Note
RADIUS and TACACS+ Security Protocols
AAA uses security protocols to administer its security functions. If your router or access server is acting as
a network access server, AAA is the means through which you establish communication between your network
access server and your RADIUS or TACACS+ security server.
The chapters in this guide describe how to configure the following security server protocols:
RADIUS
A distributed client/server system implemented through AAA that secures networks against unauthorized
access. In the Cisco implementation, RADIUS clients run on Cisco routers and send authentication
requests to a central RADIUS server that contains all user authentication and network service access
information.
TACACS+
A security application implemented through AAA that provides a centralized validation of users who
are attempting to gain access to a router or network access server. TACACS+ services are maintained
in a database on a TACACS+ daemon running, typically, on a UNIX or Windows NT workstation.
TACACS+ provides for separate and modular authentication, authorization, and accounting facilities.
SSH and Telnet
You can use the Secure Shell (SSH) server to enable an SSH client to make a secure, encrypted connection
to a Cisco NX-OS device. SSH uses strong encryption for authentication. The SSH server in the Cisco NX-OS
software can interoperate with publicly and commercially available SSH clients.
The SSH client in the Cisco NX-OS software works with publicly and commercially available SSH servers.
The Telnet protocol enables TCP/IP connections to a host. Telnet allows a user at one site to establish a TCP
connection to a login server at another site and then passes the keystrokes from one device to the other. Telnet
can accept either an IP address or a domain name as the remote device address.
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Overview
RADIUS and TACACS+ Security Protocols

SSH and Telnet
You can use the Secure Shell (SSH) server to enable an SSH client to make a secure, encrypted connection
to a Cisco NX-OS device. SSH uses strong encryption for authentication. The SSH server in the Cisco NX-OS
software can interoperate with publicly and commercially available SSH clients.
The SSH client in the Cisco NX-OS software works with publicly and commercially available SSH servers.
The Telnet protocol enables TCP/IP connections to a host. Telnet allows a user at one site to establish a TCP
connection to a login server at another site and then passes the keystrokes from one device to the other. Telnet
can accept either an IP address or a domain name as the remote device address.
IP ACLs
IP ACLs are ordered sets of rules that you can use to filter traffic based on IPv4 information in the Layer 3
header of packets. Each rule specifies a set of conditions that a packet must satisfy to match the rule. When
the Cisco NX-OS software determines that an IP ACL applies to a packet, it tests the packet against the
conditions of all rules. The first match determines whether a packet is permitted or denied, or if there is no
match, the Cisco NX-OS software applies the applicable default rule. The Cisco NX-OS software continues
processing packets that are permitted and drops packets that are denied.
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Overview
SSH and Telnet

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Overview
IP ACLs