Cisco 7800 Series Administration Manual page 99

Network Standard
DHCP option 42
DHCP option 43
DHCP option 60
DHCP option 66
DHCP option 125
DHCP option 150
DHCP option 159
DHCP option 160
Configure the Challenge for the SIP INVITE Messages
The phone can challenge the SIP INVITE (initial) message in a session. The challenge restricts the SIP servers
that are permitted to interact with the devices on a service provider network. This practice significantly
increases the security of the VoIP network through prevention of malicious attacks against the device.
Procedure
Step 1 In the phone web user interface, navigate to Admin Login > advanced > Voice > Ext(n), where n is an
extension number.
Step 2 In the SIP Settings section, choose Yes from the Auth INVITE drop-down list box.
Step 3 Click Submit All Changes.
Transport Layer Security
Transport Layer Security (TLS) is a standard protocol for securing and authenticating communications over
the Internet. SIP over TLS encrypts the SIP messages between the service provider SIP proxy and the end
user. SIP over TLS encrypts only the signaling messages, not the media.
TLS has two layers:
• TLS Record Protocol—Layered on a reliable transport protocol, such as SIP or TCH, this layer ensures
that the connection is private through use of symmetric data encryption and it ensures that the connection
is reliable.
• TLS Handshake Protocol—Authenticates the server and client, and negotiates the encryption algorithm
and cryptographic keys before the application protocol transmits or receives data.
Description
NTP server
Vendor-specific information
Vendor class identifier
TFTP server name
Vendor-identifying vendor-specific information
TFTP server
Provisioning server IP
Provisioning URL
Cisco IP Phone 7800 Series for Third-Party Call Control Administration Guide
Security Features
85