As an Ethical Hacker you are capturing traffic from your customer network with Wireshark and you need to find and verify just SMTP traffic. What command in Wireshark will help you to find this kind of

'request smtp 25' is not valid Wireshark display filter syntax and will produce a filter parse error.

In Wireshark, 'tcp.port eq 25' is valid display filter syntax that matches any TCP packet where either the source or destination port is 25, which is the standard well-known port assigned to SMTP. Wireshark display filters follow a strict field-name operator value format, and tcp.port is a recognized protocol field. This filter will capture both client-to-server and server-to-client SMTP traffic in a single expression.

'smtp port' is not recognized Wireshark display filter syntax and does not conform to the field operator value format.

'tcp.contains' checks payload byte sequences, not port numbers, making this syntactically and semantically incorrect for port-based filtering.