An engineer must configure open SIP Federation on cisco IM and presence using cisco Expressways with the additional requirement not to allow a specific list if domains and allow all other domains…

Question

Options

• AConfigure default static routes for each blocked domain with an invalid next-hop IP address.
• BAdd a static route for each blocked domain and keep the "Block Route" checkbox checked.
• CBlock the specified SIP domains on the Expressway
• DAdd each allowed domain as a SIP Federated domain.

• A
  3% (1)
• B
  5% (2)
• C
  78% (29)
• D
  14% (5)

Explanation

In an open SIP federation model on Cisco Expressway, all external domains are permitted by default. To selectively block specific domains while allowing all others, the administrator explicitly blocks those domains on the Expressway using the domain blocking feature. This is more scalable than the alternatives: adding a static route per blocked domain with an invalid next-hop would be a workaround rather than a proper configuration, and adding every allowed domain as a SIP Federated domain would be impractical in an open federation where 'allow all' is the default intent. The Expressway's domain blocking list is the correct and designed mechanism for this use case.

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