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is-port-502-open
x402
is-port-502-open is a paid API for AI agents from ip.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).
Checks whether TCP port 502 (Modbus) is open, closed, or filtered on a given host by attempting a connection from Cloudflare's edge network.
Price / call$0.01
Success—
StatusUnknown
How this service works
Is TCP port 502 (Modbus) open on a host? Attempts a connection from Cloudflare's edge and reports open/closed/filtered with the connect time; Cloudflare-fronted hosts are reported as inconclusive because their edge answers for them. Exposure checks for Modbus without running a scanner. $0.01 per check.
Output
Returns whether TCP port 502 is open, closed, or filtered on the target host, along with the connection time in milliseconds. If the host is Cloudflare-fronted, the result is marked as inconclusive because Cloudflare's edge intercepts the connection on behalf of the origin.
Example use cases
ICS device internet exposure audit
“I need to check whether port 502 is publicly reachable on our SCADA gateway at scada.mycompany.com — we want to make sure our Modbus interface isn't accidentally exposed to the internet.”
Security sweep of a PLC IP
“Can you tell me if TCP port 502 is open, closed, or filtered on the IP 203.0.113.45? We're auditing an industrial site for unintended Modbus exposure.”
Pre-deployment Modbus firewall verification
“Before we go live, check that port 502 is closed on our new edge device at plc-edge.factory.io — I need to confirm the firewall rules are blocking Modbus from the outside.”
Technical details
Endpoint
GEThttps://ip.intel.rallylive.ca/ip/port/502?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, passive check of whether Modbus (TCP port 502) is exposed on a host without running a local port scanner or installing any tooling. Ideal for security audits, compliance checks, or pre-deployment verification of OT/ICS devices. Prefer this over general-purpose port scanners when you want a lightweight, pay-per-check approach from Cloudflare's edge perspective with no setup overhead.
Side effects
- Host is Cloudflare-fronted — result returned as 'inconclusive' because Cloudflare's edge answers the connection attempt
- Host or IP unreachable — may return filtered or timeout
- Invalid hostname or IP format in query — likely 4xx error
- Connection attempt blocked by intermediate firewall — reported as filtered rather than closed
- Service temporary unavailability — upstream probe error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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