Analyze the included screenshot. What is a best practice to mitigate against this type of event?

Blocking outgoing SNMP traffic is unrelated to SQL injection, which is an application-layer vulnerability in the web server, not a network protocol issue.

Client-side filtering is trivially bypassed by an attacker who intercepts requests with a proxy tool, making it an ineffective defense against SQL injection.

Parameterized queries force the database engine to treat user-supplied input strictly as data values and never as executable SQL syntax, eliminating the possibility of injection regardless of the input content. This server-side defense in the source code is more robust than any input filtering approach because it addresses the root cause - the mixing of code and data.

Blocking non-alphanumeric characters at the server is an incomplete blocklist approach that can break legitimate inputs and may still miss injection vectors using encoded or alternative syntax.