Infraova is an email infrastructure operations platform built for agencies, deliverability consultants, and MSPs managing multiple client domains. It continuously monitors 30 infrastructure checks per domain, detects problems before clients notice, generates evidence-backed remediation proposals, executes approved changes through connected DNS providers, verifies every fix, and produces automated white-label client reports.

What email domain checks does Infraova run?

Infraova runs 30 checks per domain continuously. 25 are infrastructure checks: SPF, DKIM, DMARC, DMARC Alignment, Subdomain DMARC, MX Records, PTR/Reverse DNS, Blacklist (50+ lists), SSL Certificate, WHOIS/Domain Age, MTA-STS, TLS-RPT, SPF Enforcement, DMARC Coverage, Subdomain Lockdown, BIMI, DNSSEC, CAA Records, DANE/TLSA, Nameserver Change Detection, Registrar Lock, SPF Record Length, DKIM Key Strength, Google Bulk Sender Compliance, and Null MX. The other five are spoofing detection, Gmail reputation, domain expiry, DNS change history, and sending platform metrics.

How much does Infraova cost?

Infraova offers four plans: Starter at $99/month (up to 10 domains), Growth at $249/month (up to 40 domains, remediation proposals, white-label reports), Agency at $499/month (up to 150 domains, 15-minute monitoring, full verification), and Enterprise with custom pricing for unlimited domains. All plans include a 7-day free trial with no credit card required.

How does Infraova handle remediation?

Infraova generates specific, evidence-backed fix proposals for detected infrastructure problems. Every proposal includes the current state, proposed state, supporting evidence, and risk assessment. Your team approves the change before anything executes. Infraova never silently modifies client DNS. After execution, Infraova rescans the live record to verify the fix took effect.

Does Infraova parse DMARC aggregate reports?

Yes. Infraova ingests DMARC RUA aggregate reports from Google, Microsoft, Yahoo, and other mailbox providers. When an unauthorized sender is detected impersonating a client domain, a critical alert fires with the attacker IP, hostname, and email count.

Is there a free trial?

Yes. All Infraova plans include a 7-day free trial with no credit card required.

Infrastructure

What to do when a client domain gets blacklisted and how to catch it before the client does

Rodrigue Shema·September 23, 2026·12 min read

The moment most agencies find out about a blacklist hit

The client calls. Or emails. Or sends a Slack message that says "our emails aren't delivering."

The agency investigates. They check the domain against MXToolbox or a similar tool. They find a blacklist hit on Spamhaus, or Barracuda, or URIBL. The hit may have been there for hours. Maybe days.

The client's campaigns have been landing in spam or bouncing entirely for that entire period. Revenue has been affected. Relationships have been damaged. And the agency is now in the position of explaining why they didn't know before the client did.

This is the reactive trap for blacklist monitoring and it is the direct result of checking domains manually or intermittently instead of monitoring them continuously.

This article explains how blacklisting works, which lists actually matter in 2026, how Infraova monitors every client domain for blacklist status as part of its continuous infrastructure check, and what the operational response looks like when a hit is detected.

How email blacklisting works

An email blacklist technically a DNS-based Blackhole List (DNSBL) or Real-time Blackhole List (RBL) is a database of IP addresses and domains that have been identified as sources of spam, phishing, or malicious email.

When a receiving mail server gets an email, it queries the relevant blacklists to check whether the sending IP or the sending domain appears. If it does, the server takes action based on its configuration bouncing the message, sending it to spam, or silently discarding it.

Two types of blacklisting affect email deliverability differently:

IP blacklisting: The sending IP address is flagged. This affects all domains sending through that IP. If the IP is shared which it is on most ESPs and sending platforms a blacklist hit from one sender on the shared IP can affect every other sender on the same address.

Domain blacklisting: The domain itself is flagged. This follows the domain regardless of which IP it sends from. Switching IPs does not resolve a domain blacklist hit. The domain needs to be delisted from the specific blacklist, and the root cause needs to be fixed first.

Which blacklists actually matter in 2026

Not all blacklists carry equal weight. Being listed on an obscure regional list with minimal adoption is a different situation from being listed on Spamhaus which is queried by the majority of enterprise mail servers globally.

Infraova evaluates blacklist hits across three tiers:

Tier 1 Critical

Spamhaus DBL and Barracuda BRBL are the two blacklists with the broadest adoption among enterprise mail servers. A Tier 1 listing causes hard bounces and inbox rejection at scale across Gmail, Microsoft, Yahoo, and most corporate mail infrastructure.

A Spamhaus DBL listing is the most serious blacklist situation a domain can be in. It requires immediate action: identifying the root cause, fixing it, and submitting a delisting request at spamhaus.org/lookup. Recovery is possible but requires demonstrating that the behavior causing the listing has stopped.

A Barracuda BRBL listing is similarly impactful. Barracuda's filtering is deployed across a large number of corporate mail servers. Delisting is handled through Barracuda's removal request form.

Infraova deducts 30 points from a domain's health score for a Tier 1 blacklist hit the highest deduction of any single check.

Tier 2 Warning

URIBL, SURBL, SpamCop, and SORBS have moderate adoption. A Tier 2 listing degrades deliverability with some providers but is not as universally impactful as a Tier 1 listing.

These lists are worth addressing promptly but are not the immediate emergency that a Spamhaus or Barracuda listing represents. Each has its own delisting process URIBL through admin.uribl.com, SURBL through surbl.org, SpamCop through spamcop.net.

Infraova deducts 15 points from the domain health score for a Tier 2 hit.

Tier 3 Informational

Minor and regional lists have very limited adoption. Most major providers do not query them. A Tier 3 listing has minimal real-world impact on deliverability.

Infraova flags Tier 3 hits as warnings rather than failures and deducts only 5 points from the health score. These are worth noting but not worth alarming clients over.

The shared IP problem

For agencies managing cold email infrastructure using platforms like Instantly, Smartlead, or sending through Mailgun, SendGrid, or Postmark the sending IP is almost certainly shared.

A shared IP is used by multiple senders simultaneously. If another sender on the same shared IP sends spam, gets flagged for high complaint rates, or hits spam traps, the IP can end up on a blacklist. Every domain sending through that IP is affected including your client's domain, even if your client's sending practices are completely clean.

Infraova detects shared versus dedicated IPs by resolving the domain's primary MX host to an IP address, then checking the PTR record of that IP for shared infrastructure patterns. If the PTR contains signals like "shared", "pool", "relay", "outbound", or the hostname of a known ESP Sendgrid, Mailgun, Postmark, Instantly, Smartlead, and others Infraova flags the IP as shared and surfaces the hit as blacklist_shared_ip_hit rather than a standard domain blacklist hit.

This distinction matters for the operational response. A shared IP blacklist hit means:

The root cause is likely someone else's behavior on the same IP
Switching to a dedicated IP or a different sending platform may be the appropriate fix
Delisting the IP itself may require contacting the ESP
The domain itself may be clean the problem is the infrastructure it's sending through

A dedicated IP blacklist hit means:

The root cause is almost certainly the domain's own sending behavior or infrastructure
Authentication failures, spam trap hits, high complaint rates, or compromised infrastructure
The fix requires identifying and resolving the root cause before requesting delisting

Infraova surfaces which type of hit occurred so the team knows which response is appropriate before they start investigating.

What Infraova monitors and surfaces

Infraova runs the blacklist check as one of its 30 continuous infrastructure checks per domain. Every domain under management is checked against the full list of relevant blacklists Tier 1, Tier 2, and Tier 3 on every scan.

When a blacklist hit is detected, Infraova surfaces:

Which blacklist: The exact name of the blacklist that flagged the domain Spamhaus DBL, Barracuda BRBL, URIBL Multi, SpamCop BL, or whichever list returned a valid listing code.

The tier: Tier 1 (Critical), Tier 2 (Warning), or Tier 3 (Informational) so the team immediately understands the severity of the hit without having to research the blacklist's adoption.

The sending IP: The IP address of the primary MX host for the domain the IP that mail servers see when they receive email from this domain.

Shared or dedicated: Whether the sending IP is shared infrastructure or dedicated to this domain which determines the nature of the investigation and the appropriate fix.

The delisting URL: The exact URL where a delisting request can be submitted for the specific blacklist that flagged the domain. No searching for where to go the link is surfaced directly in the issue.

Points deducted: The impact on the domain's health score 30 points for Tier 1, 15 for Tier 2, 5 for Tier 3.

All of this is available before the client knows anything is wrong. The team sees the hit in Infraova, understands the severity and the infrastructure context, and can begin the response immediately.

The operational response when a blacklist hit is detected

When Infraova flags a blacklist hit, the operational response follows a clear sequence.

1. Assess the severity

Tier 1 hit on Spamhaus or Barracuda treat as an emergency. Campaigns should be paused immediately if active sending is happening through the affected domain. The hit is affecting deliverability to a significant portion of receiving mail servers.

Tier 2 hit treat as urgent but not an emergency. Investigate promptly. Active campaigns may need to be paused depending on the specific list and the client's sending volume.

Tier 3 hit investigate and document. Most Tier 3 listings have minimal real-world impact. Active campaigns generally do not need to be paused, but the root cause should be identified and the listing monitored.

2. Determine shared versus dedicated IP

If Infraova has flagged the hit as a shared IP hit, the investigation starts with the sending platform rather than the domain's own practices. Contact the ESP's deliverability team to understand the IP reputation situation and request a dedicated IP or IP rotation if appropriate.

If the IP is dedicated, the investigation focuses on the domain's own sending behavior and infrastructure.

3. Identify the root cause

Blacklist listings come from specific behaviors. The most common causes:

Authentication failures: A domain sending email that fails SPF and DKIM is a signal of either compromised infrastructure or misconfigured authentication. Spamhaus and other major lists use authentication failures as a listing signal. Infraova's other checks SPF, DKIM, DMARC surface authentication problems separately, often before they lead to a blacklist hit.

High spam complaint rates: Too many recipients marking emails as spam. If the domain's DMARC aggregate reports show high complaint rates from specific sending sources, those sources need to be addressed.

Spam trap hits: Sending to email addresses that exist specifically to catch senders with poor list hygiene. Spam traps never opt in, never unsubscribe, and their only function is to flag senders who are not managing their lists correctly.

Sudden volume spikes: Sending large volumes from a domain with no established sending history triggers spam filters and can cause blacklist listings.

Compromised infrastructure: A compromised mail server or sending account can generate spam traffic without the domain owner's knowledge.

The root cause must be fixed before requesting delisting. Submitting a delisting request without fixing the underlying cause results in relisting often faster than the first time.

4. Request delisting

Each blacklist has its own delisting process. Infraova surfaces the exact delisting URL for the blacklist that flagged the domain.

Spamhaus DBL: spamhaus.org/lookup/ Submit a lookup query for the domain and follow the removal process. Spamhaus requires demonstrating that the cause of the listing has been resolved.

Barracuda BRBL: barracudacentral.org/rbl/removal-request Submit a removal request with the domain and IP. Barracuda's removal process is generally faster than Spamhaus.

URIBL: admin.uribl.com Submit through the admin interface.

SURBL: surbl.org/surbl-analysis Check the listing details and follow the removal process.

SpamCop: spamcop.net/bl.shtml SpamCop listings expire automatically when the reported spam stops. No manual removal request is typically needed.

Delisting timelines vary significantly: Barracuda is typically fast (hours to days), Spamhaus can take longer depending on the nature of the listing, and SpamCop expires automatically.

5. Notify the client

The client needs to know their domain has been blacklisted what it means, which list flagged them, whether active campaigns are affected, and what is being done about it.

This notification should come from the agency before the client discovers the problem themselves. A professional, factual notification that explains the situation, the severity, the impact on deliverability, and the steps being taken demonstrates that the agency is operating the client's infrastructure proactively.

If the client discovers it first, the conversation is defensive. If the agency notifies first, the conversation is operational.

6. Monitor until clean

After a delisting request is submitted and the root cause is fixed, the domain needs to be monitored until the listing is confirmed removed. Infraova's continuous monitoring surfaces when the blacklist check returns clean the health score recovers, the issue closes, and the domain is confirmed off the list.

Why continuous monitoring matters more than periodic checks

A blacklist hit that persists for 24 hours causes 24 hours of deliverability damage. A hit that persists for a week causes a week of damage campaigns that didn't reach inboxes, clients who didn't get responses, revenue that wasn't generated.

Manual blacklist checking logging into MXToolbox or a similar tool and checking each domain individually is a periodic process. It finds blacklist hits when someone remembers to check. For an agency managing 50 client domains, that means each domain might be checked once a week at best. A hit that occurs on Tuesday and is discovered on Friday has been affecting deliverability for three days.

Infraova runs the blacklist check as part of every domain scan continuously, for every domain under management. When a hit occurs, the team knows immediately. The response starts while the damage is still minimal rather than after it has compounded.

For agencies managing many client domains, this is the operational difference between blacklist monitoring and blacklist management knowing the moment something changes and having the context to respond correctly.

The connection between authentication and blacklisting

Blacklist hits and authentication failures are often connected. A domain with missing or weak DMARC enforcement is easier to spoof and a domain that is being spoofed may end up on blacklists because of the spam being sent in its name, even though the domain owner's own sending practices are clean.

The infrastructure checks Infraova runs connect these problems explicitly. A domain with a Tier 1 blacklist hit and p=none DMARC is in a worse position than just the blacklist hit the missing DMARC enforcement means spoofed email from the domain is reaching recipients and potentially contributing to the blacklist listing.

Fixing both the blacklist hit and the DMARC policy is the complete operational response. Infraova surfaces both problems in the same infrastructure view, with the DMARC policy progression proposal available alongside the blacklist hit details.

The operational loop closes when the domain is off the blacklist, authentication is in place, and monitoring continues.

Infraova is an email infrastructure operations platform for agencies, MSPs, deliverability consultants, and businesses managing email at scale. Infraova monitors every client domain against Tier 1, Tier 2, and Tier 3 blacklists on every scan surfacing hits with severity, sending IP, shared or dedicated status, and the exact delisting URL before the client notices the deliverability impact. Start operating your infrastructure →