User's Manual  114  Document #: LTRT-10632 
 
  Mediant 800B Gateway & E-SBC 
peer certificate is received (TLS client mode, or TLS server mode with mutual 
authentication). 
 
 
Note:   
•  The device does not query OCSP for its own certificate. 
•  Some PKIs do not support OCSP, but generate Certificate Revocation Lists 
(CRLs). For such scenarios, set up an OCSP server such as OCSPD. 
 
  Private key - externally created and then uploaded to device. 
  Different levels of security strength (key size) per TLS certificate.  
  X.509 certificates - self-signed certificates or signed as a result of a certificate signing 
request (CSR). 
  Trusted root certificate authority (CA) store (for validating certificates). 
To use a TLS Context for SIPS, assign it to a Proxy Set and/or SIP Interface associated 
with the IP Group for which you want to employ TLS certificates.  When the device 
establishes a TLS connection (handshake) with a SIP user agent (UA), the TLS Context is 
determined as follows: 
  Incoming calls: 
1.  Proxy Set: If the incoming call is successfully classified to an IP Group based on 
Proxy Set (i.e., IP address of calling party) and the Proxy Set is configured for 
TLS ('Transport Type' parameter is set to TLS), the TLS Context assigned to the 
Proxy Set is used. To configure Proxy Sets, see 'Configuring Proxy Sets' on page 
380.  
2.  SIP Interface: If the Proxy Set is either not configured for TLS (i.e., the 'Transport 
Type' parameter is set to UDP) or not assigned a TLS Context, and/or 
classification to a Proxy Set fails, the device uses the TLS Context assigned to 
the SIP Interface used for the call. To configure SIP Interfaces, see 'Configuring 
SIP Interfaces' on page 357. 
3.  Default TLS Context (ID 0): If the SIP Interface is not assigned a TLS Context or 
no SIP Interface is used for the call, the device uses the default TLS Context.  
  Outgoing calls:  
1.  Proxy Set: If the outgoing call is sent to an IP Group associated with a Proxy Set 
that is assigned a TLS Context and the Proxy Set is configured for TLS (i.e., 
'Transport Type' parameter is set to TLS), the TLS Context is used. If the 
'Transport Type' parameter is set to UDP, the device uses UDP to communicate 
with the proxy and no TLS Context is used.  
2.  SIP Interface: If the Proxy Set is not assigned a TLS Context, the device uses the 
TLS Context assigned to the SIP Interface used for the call. 
3.  Default TLS Context (ID 0): If the SIP Interface is not assigned a TLS Context or 
no SIP Interface is used for the call, the device uses the default TLS Context. 
The following procedure describes how to configure a TLS Context through the Web 
interface. You can also configure it through ini file (TLSContexts) or CLI (configure system 
> tls <ID>). 
  To configure a TLS Context: 
1.  Open the TLS Contexts table (Setup menu > IP Network tab > Security folder > TLS 
Contexts). 
2.  Click New to add a new TLS Context or Edit  to modify the default TLS Context at 
Index 0; the following dialog box appears (for adding a TLS Context):