300-720 · Question #138
An administrator needs to configure a Cisco ESA to verify that a specific mail server is authorized to send emails for a domain. To reduce overhead, the administrator does not want SSL type…
The correct answer is D. Sender Policy Framework. Sender Policy Framework (SPF) is a DNS-based email authentication method that allows a domain owner to specify which mail servers are authorized to send email on behalf of that domain, using a DNS TXT record. When the Cisco ESA receives an inbound message, it performs a DNS…
Question
An administrator needs to configure a Cisco ESA to verify that a specific mail server is authorized to send emails for a domain. To reduce overhead, the administrator does not want SSL type encryption or decryption to be used in this process. What must be configured on the Cisco ESA to meet this requirement?
Options
- ADomainKeys Identified Mail
- BPKI signing keys
- CAsymmetric keys
- DSender Policy Framework
How the community answered
(28 responses)- B4% (1)
- C4% (1)
- D93% (26)
Explanation
Sender Policy Framework (SPF) is a DNS-based email authentication method that allows a domain owner to specify which mail servers are authorized to send email on behalf of that domain, using a DNS TXT record. When the Cisco ESA receives an inbound message, it performs a DNS lookup to check if the sending server's IP address matches the authorized senders listed in the SPF record. Critically, SPF involves no SSL, TLS, or any form of encryption or decryption - it is purely a DNS lookup mechanism, satisfying the administrator's requirement to avoid SSL overhead. DKIM (A) uses asymmetric cryptographic signing, which involves key-based operations. PKI signing keys (B) and asymmetric keys (C) both involve encryption/decryption processes. SPF is the only option that verifies server authorization without any encryption or decryption overhead.
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