An email server has been installed; however, the staff reports that they are unable to receive email from external email addresses, but they can email each other. Which of the following is the MOST li

The ability for staff to email each other confirms that the email server itself is operational and internal mail flow is working. The inability to receive external email, however, points to a block at the network boundary, most commonly by the company firewall, which is preventing inbound SMTP traffic (typically port 25) from reaching the email server.

A misconfigured DHCP server would primarily affect IP address assignment for clients, not specifically inbound external email connectivity to a static-IP server while internal email functions.

If the DNS server were only resolving internal namespaces, it would primarily affect the email server's ability to send outbound email to external domains or resolve external MX records, not prevent it from receiving inbound mail when internal mail works.

While DNS resolution is critical for email, explicitly configuring an email server to resolve names by IP addresses is not a standard or recommended practice for receiving external email, and DNS issues typically manifest differently than a complete block of external inbound mail.