Which two scenarios need a proper DNS configuration on Expressway servers? (Choose two.)

Question

Options

• AExpressway servers verify the common name attribute in server certificates.
• BExpressway servers route calls based on SIP URI.
• CAdmins avoid IP address configuration for neighbor zone peers.
• DExpressway servers use NTP peer authentication for secure time updates.
• EAdmins download software updates from the Cisco website via WebUI.

• A
  3% (1)
• B
  95% (36)
• E
  3% (1)

Explanation

DNS is required on Expressway when routing decisions depend on resolving hostnames or domain names rather than raw IP addresses. B is correct because SIP URI routing (e.g., [email protected]) requires Expressway to perform DNS lookups to resolve the domain portion of the URI to an IP or SRV record. C is correct because when administrators configure neighbor zone peers using FQDNs instead of IP addresses, Expressway must resolve those FQDNs via DNS. A is incorrect because certificate CN verification is handled by the TLS stack, not DNS. D is incorrect because NTP peer authentication is a time-synchronization function unrelated to DNS on Expressway. E is incorrect because software downloads via WebUI use the admin's local DNS resolver, not a DNS configuration specific to Expressway's call-routing stack.

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