What evidence do auditors commonly ask for on 1.4.2 Restricting traffic entering trusted networks from outside?

List of system components authorised to provide public-facing services, with ports and protocols; Inbound NSC rules from the internet showing only those services plus stateful return traffic; Vendor documentation confirming stateful inspection is enabled; External scan results matching the authorised public service list.

What is the most common gap auditors find on 1.4.2?

Internal hosts directly reachable from the internet because of broad NAT or permissive rules

PCI DSS v4.0.1 · Req 1: Network Security Controls

`1.4.2` Restricting traffic entering trusted networks from outside

Traffic coming into trusted networks from untrusted networks must be limited to: (a) communications with system components authorised to offer publicly accessible services, protocols and ports; (b) stateful responses to communications that system components in the trusted network started; and (c) nothing else, with all other traffic denied. Applicability: the intent concerns sessions crossing the trusted/untrusted boundary, not the details of individual protocols; UDP and other connectionless protocols may still be used if the NSC maintains state. Customized approach objective: only authorised traffic, or traffic responding to a trusted-network system component, can pass from an untrusted network into a trusted one.

Source: PCI DSS v4.0.1, 1.4.2. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open PCI DSS v4.0.1 in the compliance library.

Version 4.0.1 is the active version; 4.0 has been retired. Appendix A1 applies only to multi-tenant service providers, A2 only to card-present POS POI terminals that still use SSL or early TLS, and A3 only when a payment brand or acquirer requires it. Which requirements apply to you follows your validation type.

artefacts

held by a system

at each review

moderate

to go live

Cloud console / configuration management

where the evidence lives

teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

Inbound NSC rules from the internet showing only those services plus stateful return traffic · Cloud console / configuration management

periodic reviewEvidence produced at each review

none for this control

governing documentDocuments that govern the control

List of system components authorised to provide public-facing services, with ports and protocols · Document repository
Vendor documentation confirming stateful inspection is enabled · Vendor register / contract repository
External scan results matching the authorised public service list · Policy repository / GRC workspace

First move

Start with the 1 of 4 artefacts that already live in a system (Cloud console / configuration management); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Internal hosts directly reachable from the internet because of broad NAT or permissive rules
Stateful inspection disabled or bypassed for performance reasons
Public services placed on the internal network instead of a separated DMZ

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

1.4.1 NSCs between trusted and untrusted networks · 1.4.3 Anti-spoofing measures at trusted boundary