11.2 Configuring IP Network Interfaces .......................................................................105
11.2.1 Assigning NTP Services to Application Types ......................................................110
11.2.2 Multiple Interface Table Configuration Rules.........................................................111
11.2.3 Troubleshooting the Multiple Interface Table........................................................112
11.2.4 Networking Configuration Examples .....................................................................112
11.2.4.1 One VoIP Interface for All Applications................................................. 112
11.2.4.2 VoIP Interface per Application Type...................................................... 113
11.2.4.3 VoIP Interfaces for Combined Application Types ................................. 114
11.2.4.4 VoIP Interfaces with Multiple Default Gateways................................... 114
11.3 Configuring the IP Routing Table.........................................................................115
11.3.1 Interface Column ...................................................................................................117
11.3.2 Routing Table Configuration Summary and Guidelines........................................117
11.3.3 Troubleshooting the Routing Table .......................................................................117
11.4 Configuring Quality of Service..............................................................................118
11.5 Disabling ICMP Redirect Messages.....................................................................120
11.6 DNS......................................................................................................................120
11.6.1 Configuring the Internal DNS Table.......................................................................120
11.6.2 Configuring the Internal SRV Table.......................................................................122
11.7 Configuring NFS Settings.....................................................................................123
11.8 Network Address Translation Support .................................................................124
11.8.1 Device Located behind NAT..................................................................................125
11.8.1.1 Configuring STUN................................................................................. 125
11.8.1.2 Configuring a Static NAT IP Address for All Interfaces......................... 126
11.8.2 Remote UA behind NAT........................................................................................127
11.8.2.1 First Incoming Packet Mechanism........................................................ 127
11.8.2.2 No-Op Packets...................................................................................... 128
11.9 Robust Receipt of Media Streams .......................................................................128
11.10Multiple Routers Support......................................................................................129
11.11IP Multicasting......................................................................................................129
12 Security............................................................................................................131
12.1 Configuring Firewall Settings ...............................................................................131
12.2 Configuring 802.1x Settings.................................................................................135
12.3 Configuring General Security Settings.................................................................136
12.4 IPSec and Internet Key Exchange.......................................................................136
12.4.1 Enabling IPSec......................................................................................................137
12.4.2 Configuring IP Security Proposal Table.................................................................137
12.4.3 Configuring IP Security Associations Table...........................................................139
13 Media................................................................................................................143
13.1 Configuring Voice Settings...................................................................................143
13.1.1 Configuring Voice Gain (Volume) Control .............................................................143
13.1.2 Silence Suppression (Compression).....................................................................144
13.1.3 Echo Cancellation..................................................................................................144
13.2 Fax and Modem Capabilities................................................................................146
13.2.1 Fax/Modem Transport Modes ...............................................................................147
13.2.1.1 T.38 Fax Relay Mode............................................................................ 147
13.2.1.2 G.711 Fax / Modem Transport Mode.................................................... 148
13.2.1.3 Fax Fallback.......................................................................................... 149
13.2.1.4 Fax/Modem Bypass Mode .................................................................... 149
13.2.1.5 Fax / Modem NSE Mode....................................................................... 151
13.2.1.6 Fax / Modem Transparent with Events Mode....................................... 152
13.2.1.7 Fax / Modem Transparent Mode........................................................... 152
