Network Requirements

5.1 DNS Architecture Overview

5.1.1 Webex DNS Requirements Summary

Service	FQDN Pattern	Resolution	Purpose
Webex Calling	*.webex.com	Public DNS	Core calling services
Webex Edge	*.ucmgmt.cisco.com	Public DNS	Device management
Local Gateway	*.ciscowebex.com	Public DNS	LGW registration
Media Nodes	*.wbx2.com	Public DNS	Voice/video media
Control Hub	admin.webex.com	Public DNS	Administration

5.1.2 DNS Resolution Architecture

+-----------------------------------------------------------------+
|              DNS RESOLUTION - ABHAVTECH                          |
+-----------------------------------------------------------------+
|                                                                 |
|  INTERNAL CLIENTS              EXTERNAL RESOLUTION              |
|                                                                 |
|  +----------+    +----------+    +----------+    +----------+ |
|  | Webex App|--->| Internal |--->| Forwarder|--->| Public   | |
|  | / Phone  |    | DNS      |    | (SD-WAN) |    | DNS      | |
|  +----------+    +----------+    +----------+    +----------+ |
|                       |                               |        |
|                       | Split DNS                     |        |
|                       v                               v        |
|                  +----------+                   +----------+  |
|                  | Internal |                   | Webex    |  |
|                  | Zones    |                   | Cloud    |  |
|                  +----------+                   +----------+  |
|                                                                 |
|  KEY REQUIREMENT: No DNS interception for *.webex.com          |
|                                                                 |
+-----------------------------------------------------------------+

5.1.3 Critical DNS Rules

Rule	Requirement	Validation
No proxy	Webex domains must bypass web proxy	nslookup webex.com returns public IP
No interception	SSL inspection disabled for Webex	Certificate = DigiCert (not internal CA)
Low TTL respect	Honor TTL values (failover)	DNS cache TTL <= 300s
IPv4 preferred	Dual-stack: prefer A over AAAA	Client config or DNS policy

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