Catalyst 6500 Series SSL Services Module Configuration Note, 2.1
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Table Of Contents




The SSL Services Module is a Layer 4-through-Layer 7 service module that you can install into the Catalyst 6500 series switch. The module terminates secure sockets layer (SSL) transactions and accelerates the encryption and decryption of data used in SSL sessions.

The module operates either in a standalone configuration or with the Content Switching Module (CSM). In a standalone configuration, secure traffic is directed to the module using policy-based routing (PBR). When used with the CSM, only encrypted client traffic is forwarded to the module, while clear text traffic is forwarded to the real servers.

The SSL Services Module uses the SSL protocol to enable secure transactions of data through privacy, authentication, and data integrity; the protocol relies upon certificates, public keys, and private keys.

The certificates, which are similar to digital ID cards, verify the identity of the server to the clients. The certificates, which are issued by certificate authorities, include the name of the entity to which the certificate was issued, the public key of the entity, and the time stamps that indicate the certificate expiration date.

The public and private keys are the ciphers that are used to encrypt and decrypt information. The public key is shared without any restrictions, but the private key is never shared. Each public-private key pair works together; data that is encrypted with the public key can only be decrypted with the corresponding private key.


The SSL Services Module has these features:

Accelerates SSL transactions to help alleviate the server processing load

Enables intelligent content switching using the CSM to load balance traffic through the server

Provides centralized management (for the key, certificate, and configuration management)

Table 1-1 lists the available features.

Table 1-1 Feature Set Description 

Supported Hardware

Supervisor Engine 2 with MSFC21 and PFC22

Supervisor Engine 720 with MSFC3 and PFC3

Supported Software

Supervisor Engine 2:

Cisco IOS Release 12.1(13)E or later on the MSFC2

Cisco IOS Release 12.1(13)E3 or later on the MSFC2 and Catalyst software release 7.5(1) or later on the Supervisor Engine 2

SSL Services Module software release 2.1(1) or later on the SSL Services Module

Supervisor Engine 720:

Cisco IOS Release 12.2(14)SX1 or later on the MSFC3

Cisco IOS Release 12.2(17)SX1 or later on the MSFC3 and Catalyst software release 8.2(1) or later on the Supervisor Engine 720

SSL Services Module software release 2.1(1) or later on the SSL Services Module

SSL Features

SSL initiation3

SSL version 2.0 forwarding3

URL rewrite3

HTTP header insertion3

Wildcard proxy3

Handshake Protocol

SSL 3.0

SSL 3.1/TLS 1.0

SSL 2.0 (only ClientHello support)

Session reuse

Session renegotiation

Session timeout

Symmetric Algorithms




Asymmetric Algorithms


Hash Algorithms



Cipher Suites





Public Key Infrastructure

RSA key pair generation for certificates up to 2048-bit

Secure key storage in SSL Services Module Flash memory device

Certificate enrollment for client and server-type proxy services

Importing and exporting of key and certificate (PKCS12 and PEM)

Duplicating keys and certificates on standby SSL Services Module using the key and certificate import and export mechanism

Manual key archival, recovery, and backup

Key and certificate renewal using the CLI

Graceful rollover of expiring keys and certificates

Auto-enrollment and auto-renewal of certificates

Importing of certificate authority certificates by cut-and-paste or TFTP

Up to 8 levels of certificate authority in a certificate chain

Generating of self-signed certificate

Manual certificate enrollment using cut-and-paste or TFTP of PKCS10 CSR file

Peer (client and server) certificate authentication3

Peer (client and server) certificates3

Certificate security attribute-based access control lists3

Certificate revocation lists (CRL)3

Certificate expiration warning3

TCP Termination

RFC 1323

Connection aging

Connection rate

Up to 64,000 concurrent client connections

Up to 192,000 concurrent connections (includes 2 MSL4 )

Up to 300 Mbps throughput

NAT 5 /PAT 6

Client and server


Multiple modules in a single chassis when used with the CSM7 ; the CSM provides server load balancing (SLB8 )

High Availability

Failure detection (SLB health monitoring schemes)

System-level redundancy (stateless) (when used with the CSM)

Module-level redundancy (stateless) (when used with the CSM or with multiple SSL modules configured with HSRP3, 9 )


OIR10 (after properly shutdown)

Graceful shutdown

Password recovery3

Statistics and Accounting

Total SSL connections attempt per proxy service

Total SSL connections successfully established per proxy service

Total SSL connections failed per proxy service

Total SSL alert errors per proxy service

Total SSL resumed sessions per proxy service

Total encrypted/decrypted packets/bytes per proxy service

Statistics displayed at 1 second, 1 minute, and 5 minutes traffic rate for CPU utilization and SSL-specific counters

Certificate authentication and caching statistics3

Configuration and Management

Direct connection to the module console port

Secure Shell (SSHv1) session



Automatic backup and restore of configuration file to NVRAM

System Capacity and Performance

Supports the following RSA key sizes:






System Capacity and Performance (continued)

Up to 300 Mbps throughput

Up to 256 proxy services

Up to 64,000 simultaneous sessions

Up to 3000 sessions per second

Stores up to 356 certificates

Stores up to 356 key pairs

SNMP Support



Version string

Supported cipher suites

Trap configuration setting


Type of proxy service

IP addresses and TCP ports

Policy names

Keys and certificates


Proxy service operational status change

Proxy service certificate expiration warning


Protocol counters

Error counters

Cumulative total values are reported in get responses, even if counters are cleared using CLI commands.





Utilization of each CPU

If counters have been cleared using CLI commands, the current values are reported in get responses, and the time of the last clear command are reported.


1 MSFC = Multilayer Switch Feature Card

2 PFC = Policy Feature Card

3 New feature in SSL software release 2.1(1)

4 MSL = Maximum Segment Lifetime

5 NAT = Network Address Translation

6 PAT = Port Address Translation

7 CSM = Content Switching Module

8 SLB = Server Load Balancing

9 HSRP = Hot Standby Router Protocol

10 OIR = Online Insertion and Removal

11 All objects are read-only