About TRUNCATE
TRUNCATE (truncate.gbudb.net) is a DNSBL derived from the GBUdb (Good/Bad/Ugly database) operated by ARM Research Labs as part of the Message Sniffer email security product. GBUdb tracks IP reputation across the Message Sniffer fleet, and TRUNCATE specifically lists IPs whose 'bad' confidence is high enough that receivers should reject at SMTP-time rather than continue scoring. It's a 'shoot first, ask questions later' subset of GBUdb — high-confidence bad IPs.
Message Sniffer deployments use TRUNCATE by default — Message Sniffer is a SpamAssassin plugin and standalone scanner deployed across many small-to-mid-market mail servers. Some Postfix and Exim configs also include TRUNCATE in their DNSBL chains independently. Receiver footprint is smaller than Spamhaus but meaningful in the SMB and mid-market mail-platform population.
Sustained high 'bad' confidence in GBUdb based on aggregated reputation signals — spam classification rates across the Message Sniffer fleet, complaint reports, trap hits, and pattern analysis. TRUNCATE specifically requires the bad signal to be high-confidence; ambiguous IPs stay in GBUdb's scoring zone but don't appear on TRUNCATE.
How To Get Delisted From TRUNCATE
- 1
Confirm TRUNCATE listing via GBUdb lookup
Go to https://www.gbudb.com/truncate/index.jsp and enter your IP. The result shows whether the IP is on TRUNCATE plus its current GBUdb confidence score (the 'truncate.gbudb.net' lookup returns a 127.x.x.x response code indicating the confidence level). Higher-confidence-bad scores delist more slowly than borderline listings.
Note: GBUdb's confidence score is the underlying signal; TRUNCATE is the binary derivative. If your score is just above threshold, automatic recovery is faster than if you're deeply negative.
- 2
Diagnose the reputation signal
Because GBUdb is aggregated across the Message Sniffer fleet, the diagnosis is similar to Mailspike or Barracuda BRBL — you don't get per-classification disclosure. Investigate from your side: high bounce rates, complaint signals (Google Postmaster Tools), low engagement segments, sudden volume spikes, or content changes that match spam-classifier patterns. Cold senders most commonly trigger TRUNCATE via a combination of contaminated lists + low-personalization bulk sequences hitting Message Sniffer-protected receivers.
Note: Message Sniffer is most common in SMB and mid-market verticals — if your cold sending targets those segments heavily, the TRUNCATE exposure is higher.
- 3
Ship corrective action visible across multiple signals
Address bounce rate, complaint exposure, segmentation, and content simultaneously. Pause high-bounce sequences, verify lists through a verification service, drop never-engaged contacts, improve personalization to lower spam-classifier signal, and reduce volume to receivers in mid-market verticals where Message Sniffer is heavily deployed.
Note: Like other reputation-based lists, GBUdb recovery requires sustained clean sending — not just a one-off fix.
- 4
Submit a manual removal request via the GBUdb portal
From the GBUdb lookup page, click the contact / removal link. The form asks for the IP, a contact email on a non-listed domain, and a description of corrective action. GBUdb / ARM Research Labs reviews manual requests typically within 24-72 hours. Be specific — generic 'we have fixed the issue' messages get less priority than detailed campaign-level remediation descriptions.
Note: Manual removal of GBUdb confidence requires demonstration that the underlying signal generators (complaints, bounces, trap hits) have actually stopped.
- 5
Wait for automatic confidence recovery
GBUdb confidence scores recover gradually over 7-30 days of sustained clean sending. The recovery is statistical — every clean send improves the score, every problematic send degrades it. Once the score crosses back above threshold, TRUNCATE delists automatically without manual intervention.
Note: Manual removal followed by the same problematic behaviour re-lists within days. Sustainable recovery requires actual behaviour change.
- 6
Verify delisting and monitor longitudinally
Once delisted, re-run the GBUdb lookup to confirm. Receivers refresh DNSBL data within 1-4 hours of delisting. Monitor your GBUdb confidence score over time — a stable high-confidence-good score gives headroom and resists single bad sends from tipping you back below threshold.
Note: ColdRelay's dedicated IPs per customer isolate your GBUdb reputation from other senders — your score reflects only your sending.
Operational Details
Manual removal review: 24-72 hours with clear corrective action. Automatic confidence recovery: 7-30 days of sustained clean sending. Receiver-side DNSBL cache refresh: 1-4 hours after delisting.
Continued spam classifications from Message Sniffer fleet customers, sustained bounce rates, complaint volume, or sending patterns that pull GBUdb confidence back below threshold. Reputation-based lists are particularly sensitive to single bad campaigns post-delisting.
GBUdb lookup and removal: https://www.gbudb.com/truncate/index.jsp. ARM Research Labs / Message Sniffer support: https://www.armresearch.com/contact
TRUNCATE And Cold Email
TRUNCATE is a reputation-derived DNSBL, so the same underlying signals that hurt you on Mailspike, Barracuda BRBL, and Gmail's internal filters also hurt you on GBUdb / TRUNCATE. The trigger pattern for cold senders is multi-signal: contaminated lists driving bounces and trap hits + low-personalization content driving spam classification + volume profile matching bulk-sender heuristics. The fix is comprehensive — list hygiene + content personalization + sustainable volume profile. Shared infrastructure adds a structural amplifier: when other tenants on your IP range have weak reputation patterns, GBUdb's per-IP aggregation includes their signal in your score. ColdRelay's dedicated IPs per customer isolate this — your TRUNCATE/GBUdb score reflects only your sending. Combined with the 2-emails/day per-mailbox cap (which keeps the volume signal in the healthy range), structural TRUNCATE risk drops significantly.
Frequently Asked Questions
How long does TRUNCATE delisting take?
Manual review: 24-72 hours when corrective action is clear. Automatic confidence recovery: 7-30 days of sustained clean sending. The manual path is faster but only durable if the underlying signals have actually been addressed.
What's the difference between TRUNCATE and GBUdb?
GBUdb is the underlying reputation database — it stores per-IP confidence scores. TRUNCATE is a derivative zone listing IPs whose 'bad' confidence is high enough that receivers should reject rather than score. GBUdb's other zones return graduated confidence scores; TRUNCATE returns binary listed/not-listed for the high-confidence-bad subset.
Does TRUNCATE charge for delisting?
No — TRUNCATE / GBUdb removal is free, both via manual review and automatic confidence recovery. There's no paid-priority path.
Why is TRUNCATE used in Message Sniffer specifically?
Message Sniffer is an email security product that deploys across many SMB and mid-market mail servers. It uses GBUdb for IP reputation scoring and TRUNCATE for the high-confidence-bad cutoff — IPs on TRUNCATE get rejected at SMTP-time rather than continuing to content scoring. The receiver footprint for TRUNCATE is essentially the Message Sniffer deployed base plus some independent Postfix/Exim configs that include the zone.
Does Gmail or Microsoft 365 use TRUNCATE?
Not directly. Major providers use proprietary reputation signals rather than smaller commercial DNSBLs. TRUNCATE's direct receiver impact is at SMB and mid-market mail platforms running Message Sniffer. Indirect impact: the same signals that put you on TRUNCATE typically also degrade your reputation at Gmail and Microsoft, so a TRUNCATE listing usually correlates with deliverability issues at major providers too.
How can I improve my GBUdb confidence score?
Sustained clean sending. Reduce bounce rates (verify lists), reduce complaint exposure (better segmentation, more personalization), eliminate spamtrap hits (drop contaminated lead data), and maintain a steady volume profile that doesn't match bulk-sender heuristics. Recovery is statistical — every clean send moves the score positively, every problematic send moves it negatively.
Does ColdRelay help with TRUNCATE / GBUdb reputation?
Yes structurally: dedicated IPs per customer mean your GBUdb confidence reflects only your sending — no shared-infrastructure pollution. The 2-emails/day per-mailbox cap also keeps the volume signal healthy. Content and segmentation are still your responsibility, but the structural amplifiers (shared IPs, volume spikes from inherited senders) are removed.