The short answer
Mail Assure suits MSPs that manage email security for many clients and want a multi-tenant console, a 14-day email queue, continuity and unlimited archiving. iBlockSpam suits businesses that want to buy filtering directly, with a flat, published per-domain price, unlimited mailboxes, per-user quarantine digests, free DNS tools and a 30-day money-back guarantee.
Competitor details below were checked on N-able's own pages and documentation in October 2026.
Side by side
| Item | N-able Mail Assure | iBlockSpam |
|---|---|---|
| Who it's sold to | Managed service providers, for their clients | Businesses directly; partners (MSPs and web hosts) by conversation |
| Pricing model | By quote ("Get information on pricing") | Per domain, unlimited mailboxes (mailbox count, not message volume) |
| Published price | None | Protect $12 per domain/month billed annually ($144/year) or $15 month-to-month; Protect Plus $19 annually or $24 monthly. Beta pricing, USD, excluding tax |
| Minimum | Not published | 1 domain |
| Trial or guarantee | 30-day trial at no cost (vendor says no payment card is needed) | No free trial; 30-day money-back guarantee on a domain's first annual subscription |
| If your server is down | 14-day email queue and 24/7 continuity through a web portal | Mail spooled for up to 5 days, then delivered |
| Quarantine and reports | Partner or end-user quarantine management; Email Scout Reports up to three times daily | Personal quarantine for every user; digests hourly, daily, on a chosen weekday or custom; shared admin quarantine |
| Archiving | Long-term archiving with unlimited retention | 30-day message history only |
| Setup method | Microsoft 365 onboarding: admin consent, mailbox sync, MX update | MX change plus platform steps, with a guided setup wizard and rollback steps |
| Multi-tenant management | Multi-tenant console for MSPs | No multi-tenant console; one portal per account |
| Free tools | Not listed on the pages we checked | Email Health Check, MX, SPF, DKIM, DMARC, blacklist, PTR, MTA-STS, BIMI, header analyzer, SPF and DMARC generators |
| Contract notes | Through N-able as an MSP partner | Annual or month-to-month; cancel any time in the billing portal, effective at period end |
What it costs at 10 and 50 mailboxes
Assumptions: one domain, published prices only, USD, excluding tax.
| Item | 10 mailboxes | 50 mailboxes |
|---|---|---|
| N-able Mail Assure | Quote only (and the MSP sets the price you pay) | Quote only |
| iBlockSpam Protect, annual | $12/month ($144/year) | $12/month ($144/year) |
| iBlockSpam Protect Plus, annual | $19/month ($228/year) | $19/month ($228/year) |
| iBlockSpam Protect, month-to-month | $15/month | $15/month |
If you get Mail Assure through an MSP, its cost is usually part of a wider managed service, so compare the whole service, not just the filtering line. iBlockSpam's price covers filtering, personal quarantines, outbound relay (500 messages a month), 30-day history and domain monitoring for one domain.
When Mail Assure is the better choice
- You're an MSP managing many clients. Mail Assure's multi-tenant console and onboarding wizard are built for that. iBlockSpam has no multi-tenant console today; partners talk to us directly.
- You need a longer outage buffer. Mail Assure's 14-day queue is longer than iBlockSpam's 5-day spooling, and its continuity portal lets users keep working.
- You need archiving. Mail Assure includes long-term archiving with unlimited retention.
- You want to try before paying. Mail Assure's 30-day trial needs no credit card; iBlockSpam doesn't offer a trial.
- Your MSP already runs it and handles quarantine and support for you.
When iBlockSpam is the better choice
- You don't have an MSP, or want to own your filtering directly. You can sign up and pay per domain without a partner agreement.
- You want prices you can read. Prices and per-domain limits are on the pricing page.
- You have many mailboxes or aliases. Unlimited mailboxes and domain aliases, with 100,000 inbound messages a month per domain.
- You want each user to handle their own held mail. Personal quarantines and digests as often as hourly.
- You want your platform covered beyond Microsoft 365. Guided setup covers Microsoft 365, Google Workspace, cPanel/WHM and Exchange Server.
- You want DNS drift alerts and free tools. Domain monitoring is included, and our tools need no sign-up.
How to switch from Mail Assure
- If an MSP manages Mail Assure for you, tell them your plan and agree a cutover date and notice period.
- Export your allow and block lists, and decide where archived mail will live if you rely on Mail Assure's archive.
- Save your current DNS with the Email Health Check and lower the MX TTL a day or two ahead.
- Add your domain in iBlockSpam and follow the guided setup for your platform.
- Update any connector or firewall rule that only accepts inbound mail from Mail Assure, so mail from iBlockSpam isn't rejected.
- Change MX, test with the Email Header Analyzer, and keep Mail Assure active until the old TTL has passed and no new mail arrives there.
Our migration plan covers each step and the rollback, and the guide to switching spam filter providers explains the common pitfalls.
N-able and Mail Assure are trademarks of their owner; iBlockSpam is not affiliated with N-able.
Sources
Checked October 2026.
- N-able: Mail Assure product page (MSP focus, quote, trial without credit card, archiving, multi-tenant console, Microsoft 365 onboarding)
- N-able: email recovery (14-day email queue, 24/7 continuity, unlimited archive retention)
- N-able documentation: Start a Trial, Mail Assure (free 30-day trial, no credit card)
- N-able documentation: Protection Reports (Email Scout Reports up to three times daily)
Frequently asked questions
Can a small business buy Mail Assure directly?
N-able presents Mail Assure as a service for managed service providers to offer their clients, and pricing is by quote. If you don't work with an MSP, ask N-able how to buy. iBlockSpam sells directly to businesses at published per-domain prices, and partners agree their terms, including pricing, with us individually.
How long does Mail Assure queue mail when my server is down?
N-able's email recovery page says Mail Assure includes 14-day email queue support and 24/7 email continuity. iBlockSpam spools inbound mail for up to 5 days and delivers it when your server is back. If your outages could last longer than 5 days, Mail Assure's queue is longer.
Does iBlockSpam include email archiving like Mail Assure?
No. Mail Assure offers long-term email archiving with an unlimited retention period. iBlockSpam keeps 30 days of message history for tracing and releasing mail, which isn't a compliance archive. If you need long-term retention, keep or add a separate archive.
Is there a daily digest in Mail Assure?
N-able's documentation says Email Scout Reports can be set to run up to three times daily at chosen times, at domain level. iBlockSpam gives every user a personal quarantine with digests hourly, daily, on a chosen weekday or on a custom schedule.
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