Query Firewall Blocklist IP Trust Scores with an API

A firewall blocklist is useful for stopping suspicious traffic, but an IP address alone does not explain the wider risk. An address may be linked to phishing, malware delivery, compromised hosting, or ordinary shared infrastructure that has since been cleaned up. Checking its sender and domain reputation can help security teams decide what deserves urgent investigation.

Trusted Sender Score provides an API for integrating trust verification into security workflows. This makes it possible to query the trust score of every IP in your firewall’s blocklist, compare results with internal evidence, and send the most concerning entries to an analyst or automated response process.

For Australian organisations, this approach can suit a small business in Perth, a government supplier in Canberra, or a national retailer operating across Sydney and Melbourne. It can also reduce manual checking when a security team is managing cloud services, managed firewalls, and customer-facing systems across Australian Eastern and Western time zones.

Prepare the blocklist data

Start by exporting the firewall’s current deny list into a clean file. CSV is usually convenient, with one IP address per row and optional fields such as the detection date, firewall rule, source system, and number of blocked connections. Remove comments, duplicate entries, private addresses, and malformed values before sending anything to the API.

Separate IPv4 and IPv6 if your firewall produces both formats. Also record whether an address was blocked for email abuse, port scanning, brute-force attempts, or another event. A trust score is more useful when it is assessed alongside your own telemetry rather than treated as a complete verdict.

Set up secure API access

Create or obtain an API credential through the Trusted Sender Score platform, then store it in a secrets manager or protected environment variable. Do not place the key in a script committed to Git, a browser application, or a shared spreadsheet. Restrict access to the service account that performs reputation checks and rotate the credential according to your internal policy.

Before processing a large list, read the current API documentation for the correct base URL, authentication header, request method, response fields, and rate limits. A typical workflow sends an IP address in a request, receives its trust result, and records fields such as score, reputation indicators, and lookup status. Treat that pattern as operational guidance rather than assuming endpoint names or parameters that may change.

Send one address per request

A simple script can read each valid IP, submit it to the API, and write the response to a results file. Add a short delay or controlled concurrency so the job remains within the platform’s usage limits. Retry temporary network failures with exponential back-off, but do not repeatedly resubmit invalid addresses.

For each result, preserve the original IP, query time, score, response status, and any explanatory signals returned by the service. A timestamp matters because reputation changes. A blocklist entry created six months ago may require a different decision from an address reported repeatedly in the past hour.

Handle scores with security context

Use the score as a triage signal rather than an automatic declaration that an IP is malicious. A low-trust address connected to repeated outbound scans may justify continued blocking and deeper investigation. A moderate result from a shared hosting provider may need correlation with firewall logs, endpoint alerts, reverse DNS, and abuse reports.

When the blocked address relates to email activity, combine IP reputation with authentication evidence. The guidance on sender verification checks explains how SPF, DKIM, DMARC, and reputation information can be assessed together. This is especially relevant for Australian organisations using third-party marketing platforms or Microsoft 365 tenants.

Automate review and response

Schedule the lookup job daily, hourly, or after a significant firewall export, depending on the volume and risk. Store results in a security information and event management platform so analysts can search by IP, compare changes, and connect reputation data with Australian business hours or incident timelines. A Brisbane team, for example, can route a high-risk result to its on-call analyst before an overnight handover.

Use thresholds carefully. A high-risk score might create an alert, while a low-risk result could simply be retained for audit. Avoid automatically unblocking an address because a single check looks clean. The firewall decision should also consider active connections, internal detections, threat-intelligence feeds, and whether the IP belongs to a trusted supplier.

Expand from IP checks to domain controls

IP scoring is one layer of an email and infrastructure trust programme. If the blocklist investigation reveals spoofed domains or suspicious mail sources, review SPF, DKIM, and DMARC records for the organisation’s domains. The DMARC project guide provides a broader framework for planning authentication, reporting, and enforcement.

For organisations managing many brands, subsidiaries, or customer domains, manual review quickly becomes tedious. A bulk domain trust check can help security staff identify weak reputation or authentication settings at scale. Combined with firewall automation, API results give teams a repeatable way to prioritise threats, document decisions, and keep blocklist handling consistent across the business.