- Preface
- Using the Command-Line Interface
-
- Configuring Spanning Tree Protocol
- Configuring Multiple Spanning-Tree Protocol
- Configuring Optional Spanning-Tree Features
- Configuring EtherChannels
- Configuring Link-State Tracking
- Configuring Flex Links and the MAC Address-Table Move Update Feature
- Configuring UniDirectional Link Detection
- Configuring Resilient Ethernet Protocol
-
- Security Features Overview
- Preventing Unauthorized Access
- Controlling Switch Access with Passwords and Privilege Levels
- Configuring TACACS+
- Configuring RADIUS
- Configuring Kerberos
- Configuring Local Authentication and Authorization
- Configuring Secure Shell (SSH)
- Configuring Secure Socket Layer HTTP
- Configuring IPv4 ACLs
- Configuring IPv6 ACLs
- Configuring DHCP
- Configuring IP Source Guard
- Configuring Dynamic ARP Inspection
- Configuring IEEE 802.1x Port-Based Authentication
- Configuring Web-Based Authentication
- Configuring Port-Based Traffic Control
- Configuring IPv6 First Hop Security
- Configuring Cisco TrustSec
- Configuring FIPS
- Index
Configuring Secure Socket Layer HTTP
- Finding Feature Information
- Information about Secure Sockets Layer (SSL) HTTP
- How to Configure Secure HTTP Servers and Clients
- Monitoring Secure HTTP Server and Client Status
- Additional References
- Feature Information for SSL HTTP
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 http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information about Secure Sockets Layer (SSL) HTTP
Secure HTTP Servers and Clients Overview
On a secure HTTP connection, data to and from an HTTP server is encrypted before being sent over the Internet. HTTP with SSL encryption provides a secure connection to allow such functions as configuring a switch from a Web browser. Cisco's implementation of the secure HTTP server and secure HTTP client uses an implementation of SSL Version 3.0 with application-layer encryption. HTTP over SSL is abbreviated as HTTPS; the URL of a secure connection begins with https:// instead of http://.
Note | SSL evolved into Transport Layer Security (TLS) in 1999, but is still used in this particular context. |
The primary role of the HTTP secure server (the switch) is to listen for HTTPS requests on a designated port (the default HTTPS port is 443) and pass the request to the HTTP 1.1 Web server. The HTTP 1.1 server processes requests and passes responses (pages) back to the HTTP secure server, which, in turn, responds to the original request.
The primary role of the HTTP secure client (the web browser) is to respond to Cisco IOS application requests for HTTPS User Agent services, perform HTTPS User Agent services for the application, and pass the response back to the application.
Certificate Authority Trustpoints
Certificate authorities (CAs) manage certificate requests and issue certificates to participating network devices. These services provide centralized security key and certificate management for the participating devices. Specific CA servers are referred to as trustpoints.
When a connection attempt is made, the HTTPS server provides a secure connection by issuing a certified X.509v3 certificate, obtained from a specified CA trustpoint, to the client. The client (usually a Web browser), in turn, has a public key that allows it to authenticate the certificate.
For secure HTTP connections, we highly recommend that you configure a CA trustpoint. If a CA trustpoint is not configured for the device running the HTTPS server, the server certifies itself and generates the needed RSA key pair. Because a self-certified (self-signed) certificate does not provide adequate security, the connecting client generates a notification that the certificate is self-certified, and the user has the opportunity to accept or reject the connection. This option is useful for internal network topologies (such as testing).
If you do not configure a CA trustpoint, when you enable a secure HTTP connection, either a temporary or a persistent self-signed certificate for the secure HTTP server (or client) is automatically generated.
-
If the switch is not configured with a hostname and a domain name, a temporary self-signed certificate is generated. If the switch reboots, any temporary self-signed certificate is lost, and a new temporary new self-signed certificate is assigned.
-
If the switch has been configured with a host and domain name, a persistent self-signed certificate is generated. This certificate remains active if you reboot the switch or if you disable the secure HTTP server so that it will be there the next time you re-enable a secure HTTP connection.
Note | The certificate authorities and trustpoints must be configured on each device individually. Copying them from other devices makes them invalid on the switch. |
If a self-signed certificate has been generated, this information is included in the output of the show running-config privileged EXEC command. This is a partial sample output from that command displaying a self-signed certificate.
Switch# show running-config
Building configuration...
<output truncated>
crypto pki trustpoint TP-self-signed-3080755072
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-3080755072
revocation-check none
rsakeypair TP-self-signed-3080755072
!
!
crypto ca certificate chain TP-self-signed-3080755072
certificate self-signed 01
3082029F 30820208 A0030201 02020101 300D0609 2A864886 F70D0101 04050030
59312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274
69666963 6174652D 33303830 37353530 37323126 30240609 2A864886 F70D0109
02161743 45322D33 3535302D 31332E73 756D6D30 342D3335 3530301E 170D3933
30333031 30303030 35395A17 0D323030 31303130 30303030 305A3059 312F302D
<output truncated>
You can remove this self-signed certificate by disabling the secure HTTP server and entering the no crypto pki trustpoint TP-self-signed-30890755072 global configuration command. If you later re-enable a secure HTTP server, a new self-signed certificate is generated.
Note | The values that follow TP self-signed depend on the serial number of the device. |
You can use an optional command (ip http secure-client-auth) to allow the HTTPS server to request an X.509v3 certificate from the client. Authenticating the client provides more security than server authentication by itself.
For additional information on Certificate Authorities, see the “Configuring Certification Authority Interoperability” chapter in the Cisco IOS Security Configuration Guide, Release 12.4.
CipherSuites
A CipherSuite specifies the encryption algorithm and the digest algorithm to use on a SSL connection. When connecting to the HTTPS server, the client Web browser offers a list of supported CipherSuites, and the client and server negotiate the best encryption algorithm to use from those on the list that are supported by both. For example, Netscape Communicator 4.76 supports U.S. security with RSA Public Key Cryptography, MD2, MD5, RC2-CBC, RC4, DES-CBC, and DES-EDE3-CBC.
For the best possible encryption, you should use a client browser that supports 128-bit encryption, such as Microsoft Internet Explorer Version 5.5 (or later) or Netscape Communicator Version 4.76 (or later). The SSL_RSA_WITH_DES_CBC_SHA CipherSuite provides less security than the other CipherSuites, as it does not offer 128-bit encryption.
The more secure and more complex CipherSuites require slightly more processing time. This list defines the CipherSuites supported by the switch and ranks them from fastest to slowest in terms of router processing load (speed):
-
SSL_RSA_WITH_DES_CBC_SHA—RSA key exchange (RSA Public Key Cryptography) with DES-CBC for message encryption and SHA for message digest
-
SSL_RSA_WITH_RC4_128_MD5—RSA key exchange with RC4 128-bit encryption and MD5 for message digest
-
SSL_RSA_WITH_RC4_128_SHA—RSA key exchange with RC4 128-bit encryption and SHA for message digest
-
SSL_RSA_WITH_3DES_EDE_CBC_SHA—RSA key exchange with 3DES and DES-EDE3-CBC for message encryption and SHA for message digest
RSA (in conjunction with the specified encryption and digest algorithm combinations) is used for both key generation and authentication on SSL connections. This usage is independent of whether or not a CA trustpoint is configured.
Default SSL Configuration
The standard HTTP server is enabled.
SSL is enabled.
No CA trustpoints are configured.
No self-signed certificates are generated.
SSL Configuration Guidelines
When SSL is used in a switch cluster, the SSL session terminates at the cluster commander. Cluster member switches must run standard HTTP.
Before you configure a CA trustpoint, you should ensure that the system clock is set. If the clock is not set, the certificate is rejected due to an incorrect date.
In a switch stack, the SSL session terminates at the stack master.
How to Configure Secure HTTP Servers and Clients
Configuring a CA Trustpoint
For secure HTTP connections, we recommend that you configure an official CA trustpoint. A CA trustpoint is more secure than a self-signed certificate.
Beginning in privileged EXEC mode, follow these steps to configure a CA Trustpoint:
2.
hostname
hostname
3.
ip domain-name
domain-name
4.
crypto key generate rsa
5.
crypto ca trustpoint
name
6.
enrollment url
url
7.
enrollment http-proxy
host-name port-number
8.
crl
query
url
9.
primary name
10.
exit
11.
crypto ca authentication
name
12.
crypto ca enroll
name
DETAILED STEPS
Configuring the Secure HTTP Server
Beginning in privileged EXEC mode, follow these steps to configure a secure HTTP server:
If you are using a certificate authority for certification, you should use the previous procedure to configure the CA trustpoint on the switch before enabling the HTTP server. If you have not configured a CA trustpoint, a self-signed certificate is generated the first time that you enable the secure HTTP server. After you have configured the server, you can configure options (path, access list to apply, maximum number of connections, or timeout policy) that apply to both standard and secure HTTP servers.
To verify the secure HTTP connection by using a Web browser, enter https://URL, where the URL is the IP address or hostname of the server switch. If you configure a port other than the default port, you must also specify the port number after the URL. For example:
https://209.165.129:1026
or
https://host.domain.com:1026
1.
show ip http server status
2.
configure terminal
3.
ip http secure-server
4.
ip http secure-port
port-number
5.
ip http secure-ciphersuite {[3des-ede-cbc-sha]
[rc4-128-md5] [rc4-128-sha]
[des-cbc-sha]}
6.
ip http secure-client-auth
7.
ip http secure-trustpoint
name
8.
ip http path
path-name
9.
ip http access-class
access-list-number
10.
ip http max-connections
value
11.
ip http timeout-policy
idle
seconds
life
seconds
requests
value
DETAILED STEPS
Configuring the Secure HTTP Client
Beginning in privileged EXEC mode, follow these steps to configure a secure HTTP client:
The standard HTTP client and secure HTTP client are always enabled. A certificate authority is required for secure HTTP client certification. This procedure assumes that you have previously configured a CA trustpoint on the switch. If a CA trustpoint is not configured and the remote HTTPS server requires client authentication, connections to the secure HTTP client fail.
2.
ip http client secure-trustpoint
name
3.
ip http client secure-ciphersuite {[3des-ede-cbc-sha]
[rc4-128-md5] [rc4-128-sha]
[des-cbc-sha]}
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure
terminal
Example: Switch# configure terminal | |
Step 2 | ip http client secure-trustpoint
name Example:
Switch(config)# ip http client secure-trustpoint your_trustpoint
|
(Optional) Specifies the CA trustpoint to be used if the remote HTTP server requests client authentication. Using this command assumes that you have already configured a CA trustpoint by using the previous procedure. The command is optional if client authentication is not needed or if a primary trustpoint has been configured. |
Step 3 | ip http client secure-ciphersuite {[3des-ede-cbc-sha]
[rc4-128-md5] [rc4-128-sha]
[des-cbc-sha]} Example:
Switch(config)# ip http client secure-ciphersuite rc4-128-md5
|
(Optional) Specifies the CipherSuites (encryption algorithms) to be used for encryption over the HTTPS connection. If you do not have a reason to specify a particular CipherSuite, you should allow the server and client to negotiate a CipherSuite that they both support. This is the default. |
Step 4 | end
Example: Switch(config)# end |
Monitoring Secure HTTP Server and Client Status
Command |
Purpose |
---|---|
show ip http client secure status |
Shows the HTTP secure client configuration. |
show ip http server secure status |
Shows the HTTP secure server configuration. |
show running-config |
Shows the generated self-signed certificate for secure HTTP connections. |
Additional References
Related Documents
Related Topic | Document Title |
---|---|
Configuring Identity Control policies and Identity Service templates for Session Aware networking. |
Session Aware Networking Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) |
Configuring RADIUS, TACACS+, Secure Shell, 802.1X and AAA. |
Securing User Services Configuration Guide Library, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) |
Error Message Decoder
Description | Link |
---|---|
To help you research and resolve system error messages in this release, use the Error Message Decoder tool. |
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi |
Standards and RFCs
Standard/RFC | Title |
---|---|
MIBs
MIB | MIBs Link |
---|---|
All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Technical Assistance
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Feature Information for SSL HTTP
Release | Feature Information |
---|---|
Cisco IOS 15.0(2)EX1 | This feature was introduced. |