DNS SRV Records for Open XMPP Federation with Cisco Unified Communications Manager IM & Presence

Explanation.

To support open XMPP federation in Cisco Unified Communications Manager IM & Presence, the following DNS SRV record(s) must be created in the public DNS server:

C. _xmpp-server_tls.customer.com

Explanation:

• XMPP is an open standard for messaging and presence information exchange. It uses DNS SRV records to locate XMPP servers on the internet.
• In order to enable XMPP federation, the XMPP server ( Cisco Unified Communications Manager IM & Presence) must be accessible from the internet and its XMPP service must be discoverable by other XMPP servers.
• The DNS SRV record for XMPP server must be created with the following format: _xmpp-server_protocol.domain, where "protocol" is the transport protocol used by the XMPP server, such as TCP or TLS, and "domain" is the domain name of the XMPP server.
• In this case, the XMPP server is using the default domain name scheme with domain "customer.com", and the transport protocol used is TLS. Therefore, the DNS SRV record that needs to be created is "_xmpp-server_tls.customer.com".
• Option A, "_xmpp-server_tcp.customer.com" is incorrect because it specifies TCP protocol instead of TLS, which is the recommended protocol for XMPP communication.
• Option B, "_xmpp-client_tls.customer.com" is incorrect because it specifies the client role, not the server role. DNS SRV records for XMPP servers should use "xmpp-server" prefix, not "xmpp-client".
• Option D, "_xmpp-server_udp.customer.com" is incorrect because UDP is not a recommended transport protocol for XMPP communication. TCP or TLS is recommended.
• Option E, "_xmpp-client_tcp.customer.com" is incorrect for the same reason as option B.