Data Loss Prevention Services for Microsoft 365
Most data leaves a business by accident: a spreadsheet of client account numbers forwarded to a personal Gmail, a patient list copied to a USB stick, a contract shared with 'anyone with the link'. Data loss prevention services catch those moments in Microsoft 365, warn the person, and block the ones that matter, using the Purview tools already in your tenant.
The short answer
Data loss prevention software finds sensitive information, such as Social Security numbers, card and bank data, health records and client files, and controls what can happen to it: warn the person, encrypt it, block the share or stop the copy to a USB drive. In Microsoft 365 that software is Microsoft Purview, with DLP policies across Exchange, SharePoint, OneDrive, Teams and Windows and macOS devices, and sensitivity labels that travel with the document. NetSys designs the policies around the data your business handles, tunes them so staff are coached rather than blocked, and reports what HIPAA, FTC Safeguards, NY DFS and cyber-insurance reviews ask for, inside the managed agreement and remotely anywhere in the United States.
DLP has a reputation for being switched on with enthusiasm and off within a month, because the first policy blocked the CFO's board pack and generated four hundred alerts nobody could read. The product was rarely the problem. The policy was written to find everything instead of the handful of data types that would cause a breach notification if they walked out the door.
We start from that handful. An accounting firm cares about tax identifiers and bank details; a medical practice about patient identifiers; a law firm about client matter files; an importer about pricing sheets and customer lists. Policies are built around those, run in audit mode until the false positives are understood, then enforced in stages. Our DLP FAQ post answers the questions owners usually ask before starting.
Find the Data, Coach the Person, Block the Exit
Discovery comes first: Purview's classifiers and a content scan show where sensitive data already sits in SharePoint, OneDrive and mailboxes, which is usually more places than expected. We define sensitivity labels (Public, Internal, Confidential, Restricted) with encryption and sharing limits attached to the top tiers, and auto-labeling for the patterns classifiers can catch. DLP policies then apply across email, files, Teams and endpoints, starting with policy tips that explain the rule and let the person justify an override. Only the highest-risk actions are hard-blocked: bulk external sharing of restricted files, USB copies of labeled data, email of unencrypted identifiers outside the domain. Monthly, we review overrides and alerts with you and adjust.
What Data Loss Prevention Services Cover
Discovery and Classification
You cannot protect data you have not found.
- Content scan across SharePoint, OneDrive, Exchange and Teams for sensitive information types
- Custom classifiers for your identifiers: client numbers, matter codes, part pricing, patient IDs
- Trainable classifiers for contracts, financial statements and source code
- Report of where the sensitive data lives and who has access to it
Sensitivity Labels
Protection that travels with the document.
- Label scheme designed with you, with encryption and sharing limits on the top tiers
- Auto-labeling for recognizable patterns; manual labeling with sensible defaults for the rest
- Labels applied to SharePoint sites and Teams so new files inherit protection
- Encrypted documents that still open for the outside parties who should see them
Email and Endpoint DLP
The two exits that matter most.
- Exchange policies that warn, encrypt or block mail carrying sensitive data outside the domain
- Endpoint DLP on Windows and macOS: USB copy, print, upload to personal cloud, paste into unapproved sites
- Teams and SharePoint sharing rules for external guests and anonymous links
- Integration with email encryption so the safe path is the automatic one
Tuning and Reporting
Coach first, block second, report monthly.
- Audit mode before enforcement so false positives are found before anyone is blocked
- Policy tips written in plain language, with justified overrides logged
- Monthly review of alerts and overrides, with adjustments to the rules
- Evidence for HIPAA, FTC Safeguards, NY DFS, PCI DSS and cyber-insurance reviews; included in the NetSys agreement
Why Businesses Choose NetSys for Data Loss Prevention
Fifteen minutes with a NetSys engineer, not a salesperson, and you will know where your data loss prevention (dlp) stands and what it would take to fix it. Call 845-203-3914 or request a call to discuss the scope and next steps.
Who does the work: meet the NetSys team on our About page.
- Policies built around the few data types that would trigger a breach notification, not around everything
- Audit mode and policy tips first, so DLP coaches staff instead of blocking the business
- Uses the Microsoft Purview licensing most Microsoft 365 Business Premium tenants already hold
- Endpoint DLP included, because the USB stick and the personal cloud upload are where leaks happen
- Run by the team that manages your email encryption and Microsoft 365 tenant
- Month to month, like every NetSys agreement
Where we deliver Data Loss Prevention (DLP)
Data Loss Prevention (DLP) in New York City · Data Loss Prevention (DLP) in Westchester County · Data Loss Prevention (DLP) in Fairfield County · Data Loss Prevention (DLP) in New Jersey. We also support clients remotely wherever their systems run. See all locations and service areas.
Data Loss Prevention (DLP) FAQs
What is data loss prevention?
Data loss prevention is a set of policies and tools that detect sensitive information in email, files, chat and on devices, and control what can happen to it: warn the user, require encryption, block external sharing or stop a copy to removable media. In Microsoft 365, Purview DLP and sensitivity labels provide it. NetSys designs, tunes and runs those policies for small and mid-sized businesses.
How do you implement data loss prevention?
Start with the handful of data types that would trigger a breach notification or hurt a client relationship, not everything. Run a discovery scan to see where that data already sits in SharePoint, OneDrive and mailboxes, then set up sensitivity labels with encryption and sharing limits on the top tiers. Write DLP policies for email, files, Teams and devices and run them in audit mode until the false positives are understood. Enforce in stages, with policy tips and justified overrides first and hard blocks only for the short list of high-risk actions you approve, then review alerts and overrides monthly.
What is included in data loss prevention services?
At NetSys: a discovery scan and a report of where sensitive data lives and who can reach it; custom classifiers for your own identifiers; a sensitivity label scheme with auto-labeling where patterns allow; DLP policies for Exchange, SharePoint, OneDrive, Teams and Windows and macOS devices; email encryption tied in so the safe path is automatic; plain-language policy tips; and a monthly review of alerts and overrides with evidence for HIPAA, FTC Safeguards, NY DFS, PCI DSS and cyber-insurance reviews.
Do we need data loss prevention services if we already have email encryption?
Encryption protects the message you chose to encrypt. DLP decides which messages and files need protection and applies it whether or not the sender remembered, and it covers the exits encryption does not: SharePoint links, Teams chats, USB drives, personal cloud uploads and printing. The two work together, and we run both from the same Purview console.
Will DLP block our staff from doing their jobs?
Not if it is tuned, which is the part most rollouts skip. We run every policy in audit mode first, review what it would have blocked, and fix the false positives before enforcement. Most rules then show a policy tip and allow a justified override, so the person is coached rather than stopped. Only a short list of high-risk actions is hard-blocked, and you approve that list.
What data should a small business protect with DLP?
The data whose loss would trigger a legal notification or a client-relationship problem: Social Security and tax identifiers, bank and card details, health information, client files under privilege, employee records, and the business's own pricing and customer lists. Compliance obligations (HIPAA, FTC Safeguards, NY SHIELD, DFS, PCI) define part of the list; the rest comes from a conversation with you about what would hurt.
How much do data loss prevention services cost?
DLP design, tuning and ongoing management are included in the all-inclusive month-to-month NetSys managed agreement. Purview DLP and sensitivity labels are part of Microsoft 365 Business Premium; some advanced classifiers and endpoint features need higher licensing, which we identify before starting. Businesses with internal IT can engage a DLP rollout as a fixed-scope project, quoted after the discovery scan. That quote moves with the number of users and devices, how many data types and custom classifiers you need, how much sensitive data the scan finds and where, whether endpoint DLP or advanced classifiers need licensing beyond Business Premium, and the compliance reporting you have to produce.
Who handles support and escalations?
Staff who hit a policy tip or a block call the NetSys help desk, staffed seven days a week from 4 a.m. to 11 p.m. Eastern, which explains the rule and records a justified override. Changes to what is blocked are approved by the person you name, and alerts and overrides are reviewed with you every month. Activity that looks like a deliberate leak goes straight to the contacts you name and is handled as a security incident.
How do we get started with DLP?
The free assessment is a remote external penetration test, limited to the information available to NetSys and the external scope we agree with you. DLP planning, Microsoft 365 data discovery, sharing and licensing review require a separate agreed scope. Call 845-203-3914 or use the contact page to discuss the next step.
Guides on this topic
Stop the leak that becomes a breach notification.
The policy is built around the few data types that would force you to notify someone, usually a short list: patient identifiers, or the account numbers on an invoice. A Purview scan shows where those already sit in SharePoint, OneDrive, Teams and mailboxes. Enforcement waits until audit mode is quiet.