Cisco Systems and the ASA Services Module Manual De Usuario

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Cisco ASA Series Firewall CLI Configuration Guide
 
Chapter 20      Configuring Cisco Intercompany Media Engine Proxy
  Configuring Cisco Intercompany Media Engine Proxy
Creating the TLS Proxy 
Because either enterprise, namely the local or remote Cisco UCM servers, can initiate the TLS 
handshake (unlike IP Telephony or Cisco Mobility Advantage, where only the clients initiate the TLS 
handshake), you must configure by-directional TLS proxy rules. Each enterprise can have an ASA as the 
TLS proxy.
Create TLS proxy instances for the local and remote entity initiated connections respectively. The entity 
that initiates the TLS connection is in the role of “TLS client.” Because the TLS proxy has a strict 
definition of “client” and “server” proxy, two TLS proxy instances must be defined if either of the 
entities could initiate the connection.
The example command lines in this task are based on a basic (in-line) deployment. See 
 for an illustration explaining the example command lines in this task.
To create the TLS proxy, perform the following steps:
Command
Purpose
Step 1
hostname(config)# tls-proxy proxy_name
Example:
hostname(config)# tls-proxy local_to_remote-ent
Creates the TLS proxy for the outbound 
connections. 
Step 2
hostname(config-tlsp)# client trust-point 
proxy_trustpoint 
Example:
hostname(config-tlsp)# client trust-point local-ent
For outbound connections, specifies the trustpoint 
and associated certificate that the adaptive security 
appliance uses in the TLS handshake when the 
adaptive security appliance assumes the role of the 
TLS client. The certificate must be owned by the 
adaptive security appliance (identity certificate). 
Where proxy_trustpoint specifies the trustpoint 
defined by the crypto ca trustpoint command in 
 in 
Step 3
hostname(config-tlsp)# client cipher-suite 
cipher_suite 
Example:
hostname(config-tlsp)# client cipher-suite 
aes128-sha1 aes256-sha1 3des-sha1 null-sha1
For outbound connections, controls the TLS 
handshake parameter for the cipher suite. 
Where 
cipher_suite
 includes des-sha1, 3des-sha1, 
aes128-sha1, aes256-sha1, or null-sha1. 
For client proxy (the proxy acts as a TLS client to 
the server), the user-defined cipher suite replaces the 
default cipher suite, or the one defined by the ssl 
encryption
 command. Use this command to achieve 
difference ciphers between the two TLS sessions. 
You should use AES ciphers with the Cisco UCM 
server. 
Step 4
hostname(config-tlsp)# exit
Exits from the TLS proxy configuration mode.
Step 5
hostname(config)# tls-proxy proxy_name
Example:
hostname(config)# tls-proxy remote_to_local-ent
Create the TLS proxy for inbound connections.