With Split Horizon DNS mapping, clients can be supported inside and outside the firewall of an enterprise.
The Dynamic Configuration service output contains different settings, such as, ESMSRVR, CESSRVR, DIRSRVR, SIP_CONTROLLER_LIST, CONFERENCE_PARTICIPANT_URL, APPCAST_URL. These settings can contain IP addresses. To replace the IP addresses with appropriate FQDNs for these settings in the Dynamic Configuration service output, enable the Split Horizon DNS mapping feature.
Note:
If you are using automatic configuration to provide 46xxsettings.txt files to endpoints, you must republish the Group and Phone Model settings after updating Split Horizon DNS mapping. Otherwise, 46xxsettings.txt files will not contain the updated configuration parameters.
For example, a Presence server is located internally in an enterprise network and also has Network Address Translation (NAT) access from outside the enterprise using the internet. In this case, there will be two Presence server IP addresses for the clients.
For the Presence server, the internal IP address is 190.160.10.1 and external IP address is 90.165.14.11:
On the Configurations page, you can use any of these two IP addresses as the value for the PRESENCE_SERVER setting.
FQDN of the Presence server is pserver1.avaya.com.
To configure Split Horizon DNS mapping, you need to map the Presence server IP address to the Presence server FQDN. When you enable Split Horizon DNS mapping, the internal and external clients receive the PRESENCE_SERVER setting with the same value (FQDN): pserver1.avaya.com.
