Spam and phishing arrive every day
If that's happening to you, your server's filter has fallen behind. Shield filters at the domain's entrance, before the message ever touches your server.
Spam doesn't have to reach your server
Keeping an antispam up to date on your own server is work: rules, blocklists, updates, and a server spending resources on junk. lua Shield takes over that part at the domain's entrance, and your server stays exactly where it is.
For those who run their email server in-house and are tired of spam
Shield is for the company or provider that has Exchange, Zimbra, cPanel or Postfix running and doesn't want to migrate just to solve spam.
Maintaining antispam takes work
Rules, blocklists and updates take up IT time. With Shield, that part is handled by people who fight spam every day.
Email has to stay on the company's server
Because of internal policy, a contract or an industry requirement. The protection comes from outside, and the mailboxes and data stay where they are.
How it works, in three steps
The domain's MX points to Shield, which filters and delivers to your server.
Email from the internet
lua Shield filters, flags the suspicious and rejects the spam
Your server and your mailboxes
1
Server assessment
You tell us which server you use and how many mailboxes you have. We check the path and guide the activation.
2
Prepare the server
Allow Lua's IPs and create the rule that moves flagged spam to the right folder, with step-by-step instructions for Zimbra, Exchange, Postfix and cPanel in the documentation.
3
Test period and MX switch
Lua's MX goes in with the same priority and the same TTL as your current MX, and the old one stays valid in case anything goes wrong. After the test period, the domain keeps only Lua's MX, and the server accepts port 25 only from Lua.
Who is behind the filter
Fighting spam is what our engineering team does every day, with more than 20 years of email experience on the team. The same filter protects lua.email mailboxes, lua Bridge domains and lua Shield servers.
99.91% antispam accuracy Measured by users' own corrections: every message taken out of Spam or sent there counts as a filter error.
1+ billion messages analyzed By the antispam filter, counting those refused on arrival and those delivered.
20+ years of email experience Combined across the engineering team that runs delivery, antispam and technical support.
Several layers on every message
Sender reputation, SPF, DKIM, DMARC and ARC verification, content and link analysis, neural network AI and antivirus on attachments. See it layer by layer.
Learns from recipients and from spamtraps
Every user correction goes into the training, and our spamtraps (trap addresses that only receive spam) teach the filter about new campaigns. If a message slips through, you send it through the panel and the filter learns.
Our own lists, not generic ones
Besides the international lists, we maintain our own RBL of servers and networks and lists of sender domains and scam links, built from the email that reaches Brazil. How the lists work.
Lists by domain and by mailbox
Allowed or blocked senders and domains, for the whole domain or for a single mailbox. The important supplier always gets through.
People watching the filter
Our team tracks false positives, new phishing campaigns and the rules every day. If something slips through, you let the team know and they adjust the filter with you.
Why choose lua Shield
Built for your own server
Exchange, Zimbra, cPanel, Postfix or any server that receives email over SMTP. You keep your infrastructure.
A filter that learns
Every message a user takes out of Spam or sends there teaches the filter. Going by those corrections, accuracy is 99.91%. How the antispam works
Flags, doesn't delete
Suspicious messages reach your server flagged, and only what is clearly spam is rejected, with the reason in the panel and a bounce to the sender. A legitimate email doesn't vanish without a trace.
A lighter server
Your server no longer has to run and update its own antispam. Less maintenance for your IT team.
Activation without migration
Just point the domain's MX to lua Shield. The mailboxes, users and data stay on your server. Activation step-by-step
Human support in Brazil
You allow and block senders and adjust the destination server through the panel, and our support walks you through the activation, in Portuguese.
More security for your company's operations
Phishing and spam put your company's data at risk. lua Shield blocks those messages at the domain's entrance, 24 hours a day.
- Spam and phishing identified and flagged at the door
- Filter kept up to date by our team, with no work for your IT
- Less load on your email server
- A cleaner inbox for the whole team
lua Shield use cases
Situations where Shield solves the problem at the door, without touching the mailboxes.
On-premises Exchange with a lot of spam
Exchange stays in-house. Shield filters at the door, and a transport rule moves anything flagged to the junk folder.
Zimbra, cPanel or Postfix with an outdated antispam
The server works well and the filter has aged. Shield takes over the entrance, and the server stops spending resources on junk.
Split domain, with some accounts outside the server
Some accounts stay on the server and some move to lua.email, on the same domain. With accounts on Lua, the setup is the one from lua Bridge, and that's the way to leave the server gradually.
Internet provider with customer domains
Whoever has their own email service protects customers' domains, one by one, without migrating anyone, and can offer this in their reseller program.
Prefer that our team contacts you? Leave your contact details
What you see day to day
The filter sits at the door, and the panel shows what it did. The real screens are at the top of this page.
- Domain statistics: what arrived, what was delivered, flagged as spam and rejected.
- The trace of each message, with the result and the reason, to answer "the email didn't arrive".
- Rejections at the door, with the reason in Portuguese.
- Allowed and blocked sender lists by domain and by mailbox.
- What to do when a message slips through: you send the message to the filter through the panel, and the documentation explains how.
Anything that arrives flagged goes to your server's spam folder through the rule you created at activation. What stays in the folder is spam the filter is unsure about: what is clearly spam never gets in.
How to start without changing anything on the server
Shield starts with one domain and has a technical phase at the MX switch, with the old MX still published.
1
Start with one domain
Pick the lowest-risk domain or the one that gets the most spam.
2
Run the activation tests
Check that the flagged message goes to the spam folder, that normal delivery works and that a nonexistent recipient is rejected, following the test list.
3
Compare
See in the panel what the filter rejected, flagged and delivered, and compare it with the spam that used to arrive.
The license costs R$ 2.50 per account, per month, and is subscribed to directly at checkout. Each license is tied to a domain in the panel. For large volumes, talk to sales and we'll put together a proposal.
Who benefits most from lua Shield
Companies with on-premises Exchange
They keep Exchange in-house and want better spam filtering without changing platforms.
Zimbra, cPanel or Postfix servers
Servers that work well but whose antispam has fallen behind. Shield fixes it at the door.
Those who need to keep email in-house
Because of internal policy, a contract or an industry requirement, email stays on the company's server. The protection comes from outside, without touching the data.
Internet providers and resellers
Anyone with their own email server and service protects their own domains and their customers' domains, without migrating anyone, and can resell the protection. Reseller program with your brand
Fighting spam is our everyday work, and our engineering team has more than 20 years of email experience.
Also take a look at
In every product
Filtering at your domain's entrance
lua Shield applies antispam, antivirus and sender lists before the email reaches your server, with the same filter that protects lua.email mailboxes. Protection details
Antispam at the door
99.91% accuracy in inbound filtering: spam and phishing are stopped along the way before they reach your server.
Antivirus on attachments
Threat analysis of attachments and suspicious content at the edge of the domain, without overloading your server.
Allowed and blocked senders
Trusted or blocked senders and domains, for the whole domain or for a single mailbox.
No migration
Works with the server you already have: only the domain's MX changes.
Questions about lua Shield
Can I start with one domain?
Yes, you can start with one domain. At the MX switch there is a technical test period, during which the old MX stays published, and the license is per account, at R$ 2.50 per month, tied to the domain in the panel. Subscribe at checkout for that domain's accounts and add more later. For large volumes, we put together a proposal.
What does IT need to do to activate it?
Allow Lua's IPs in the server's firewall and antispam, create the rule that moves flagged spam to the right folder, and change the domain's MX. If the server accepts any recipient and bounces later, the documentation also shows how to reject addresses that don't exist.
Can I protect several domains?
Yes. Each domain is activated with its own MX, and all of them appear in the same panel. If you have several domains, each R$ 2.50 per account, per month license is tied to the domain in the panel, and for large volumes we put together a proposal.
What if some accounts leave the server?
You can split the domain: whatever the server doesn't know goes on to Lua. With accounts on lua.email, the setup becomes that of lua Bridge, which also routes by account.
Do I need to replace my email server?
No. lua Shield sits at the entrance of your domain, filters, and delivers to the server you already have. Mailboxes, users and data stay on it.
Is spam blocked or just flagged?
Both, depending on how sure the filter is. Anything suspicious reaches your server with a flag, so a simple rule can move it to the spam folder. What is clearly spam is rejected at the door: the sender gets a bounce and the rejection shows up in the panel with the reason. That way no legitimate email disappears without you knowing.
Does it work with Exchange, Zimbra, cPanel or Postfix?
Yes. It works with any server that receives email over SMTP. Just point the domain's MX to lua Shield. The rule for moving flagged spam on each server is in the lua Shield documentation.
I use Google Workspace or Microsoft 365. Does Shield work?
Shield was designed for your own server. For Google and Microsoft, lua Bridge already applies the same antispam to those accounts and also lets you keep part of the team on lua.email. Talk to sales to evaluate your case.
How much does lua Shield cost?
lua Shield costs R$ 2.50 per account, per month. The license is per account and tied to the domain in the panel. Subscribe directly at checkout; for large volumes, talk to sales and we'll put together a proposal.
The same filter that protects lua.email mailboxes
Neural network AI, our own RBL and domain lists, spamtraps and antivirus. See, layer by layer, how the filter decides what reaches your server.
Assessment of your server
Tell us which server you use and how many mailboxes you have. We'll show you how to activate lua Shield without interrupting your company's email.
Request an assessment on WhatsAppPrefer that our team contacts you? Leave your contact details
IT firm or reseller?
Protect your customers' servers with Shield and earn from the reseller program, even under your own brand.
Reseller program under your brand