## Private network links to Microsoft SQL Server

URL: https://docs.atlan.com/apps/connectors/database/microsoft-sql-server/how-tos/private-network-links-to-microsoft-sql-server

> Connect Atlan to a SQL Server that has no public access, over AWS PrivateLink or Azure Private Link - one common five-phase pattern covering EC2, RDS, Azure VM, and Azure SQL Database / Managed Instance.

Connect Atlan to a SQL Server that has no public access, over AWS PrivateLink or Azure Private Link. One common pattern covers all four variants - SQL Server on EC2, on RDS, on an Azure VM, and Azure SQL Database / Managed Instance. This page is the overview: the shared phases, the intake checklist, and the approval handshake. The cloud-specific guides linked below carry the detailed console steps.

> **Note: New to private links?**
>
>
> Read [How SQL Server connectivity works](https://docs.atlan.com/llms/connectors/microsoft-sql-server/how-sql-server-connectivity-works/llms.txt) first. The plug (endpoint), the socket (service), the approval handshake, and the "which string goes where" table are all introduced there.
>

## Which variant am I?

| Your SQL Server runs on | What you build on your side | Detailed guide |
|---|---|---|
| Amazon EC2 | Internal Network Load Balancer + endpoint service | [EC2 guide](https://docs.atlan.com/llms/connectors/microsoft-sql-server/set-up-a-private-network-link-to-microsoft-sql-server-on-amazon-ec2/llms.txt) |
| Amazon RDS | Internal NLB (targeting the RDS IP or, better, an RDS Proxy) + endpoint service | [RDS guide](https://docs.atlan.com/llms/connectors/microsoft-sql-server/set-up-a-private-network-link-to-microsoft-sql-server-on-amazon-rds/llms.txt) |
| Azure Virtual Machine | Standard internal load balancer + Private Link service | [Azure VM guide](https://docs.atlan.com/llms/connectors/microsoft-sql-server/set-up-a-private-network-link-to-sql-server-on-azure-virtual-machine/llms.txt) |
| Azure SQL Database / SQL Managed Instance | Nothing - the service natively supports private endpoints; you collect identifiers and approve | [Azure SQL Database guide](https://docs.atlan.com/llms/connectors/microsoft-sql-server/set-up-a-private-network-link-to-azure-sql-database/llms.txt) |

## Five phases at glance

| Phase | What happens | Owner | Typical time |
|---|---|---|---|
| 1. Prepare the socket | Build the load balancer + service (VM/EC2/RDS) or just collect identifiers (Azure SQL) | Your cloud/network team | 1-3 hours (or 10 min for Azure SQL) |
| 2. Share the intake packet | Send Atlan everything it needs, in one ticket | Atlan User | 15 minutes |
| 3. Atlan builds its endpoint | Endpoint created in your tenant's network; goes to pending | Atlan support | 1-2 business days |
| 4. Approve and open firewalls | Approve the pending connection; add NSG/SG rules for Atlan's private CIDR | Your cloud/network team | 30 minutes |
| 5. Connect and verify | Point the crawler at the endpoint DNS name and test | Atlan User | 30 minutes |

## Phase 1 - Prepare socket

**Owner:** Your cloud/network team

Follow the detailed guide for your variant (table above). In summary:

- **AWS (EC2 or RDS):** create a target group (protocol TCP, your SQL port), register the instance (or the RDS IP), create an internal Network Load Balancer, and wait until the target shows **Healthy** - an unhealthy target is the top cause of "endpoint approved but connection times out". Then create a VPC endpoint service on the NLB and add Atlan's AWS account ID (from support) as an allowed principal.
- **Azure VM:** create a Standard internal load balancer (TCP health probe on 1433, backend pool = the VM), verify the probe shows **Healthy**, create a Private Link service on the frontend, and copy the **PLS alias**.
- **Azure SQL Database / Managed Instance:** nothing to build. Collect the server or Managed Instance **Resource ID** (Overview → JSON view), the fully qualified server name, and for failover groups the listener FQDN.

> **Caution: RDS target IPs change**
>
>
> Registering the RDS instance's current IP pins the NLB to an address that can change on failover or maintenance, silently breaking the link later. Prefer an **RDS Proxy** as the target, or put a process in place to re-register the IP. See the [RDS guide](https://docs.atlan.com/llms/connectors/microsoft-sql-server/set-up-a-private-network-link-to-microsoft-sql-server-on-amazon-rds/llms.txt).
>

## Phase 2 - Share intake packet

**Owner:** Atlan User

Multi-day back-and-forth on private link tickets almost always comes from missing intake information. Send all of this in your first message:

- Your Atlan tenant URL
- The service identifier: endpoint service name (AWS), PLS alias or Resource ID (Azure VM), or server/MI Resource ID (Azure SQL)
- The server hostname (FQDN) the crawler should ultimately use - including failover-group listener names if any
- The port, if it isn't 1433
- The Azure region / AWS region and availability zones of the service - Atlan's endpoint must be compatible; for AWS, either match AZs or enable cross-zone load balancing on your NLB
- The authentication method you'll use (basic / service principal / NTLM)
- Who on your side will approve the pending connection (name the role, not a person)

## Phase 3 - Atlan builds its endpoint

**Owner:** Atlan support

Atlan creates a private endpoint in your tenant's network targeting your socket - typically within 1-2 business days. The endpoint connection moves through this lifecycle:

1. **Created** - Atlan builds the endpoint (this phase).
2. **Pending** - waiting for your approval. Connections time out in this state.
3. **Approved** - you approved; traffic flows within minutes.
4. **Usable** - proceed to Phase 5.

Support replies with the **endpoint DNS name** for Phase 5, and (if a firewall stays active on your side) Atlan's **private source CIDR** for Phase 4.

## Phase 4 - Approve and open remaining firewalls

**Owner:** Your cloud/network team

1. **Approve the pending connection.** AWS: VPC console → **Endpoint services** → your service → **Endpoint connections** → **Accept**. Azure: Private Link Center → your PLS (or the Azure SQL server → **Private endpoint connections**) → **Approve**. Nothing approves itself - someone must click.
2. **Open the path behind the socket.** The private link delivers traffic to your subnet - your NSG / security group / Windows Firewall still applies. Add an inbound rule allowing TCP 1433 from Atlan's **private source CIDR** (from your ticket - the public NAT IPs are irrelevant here). On AWS, note that "Enforce inbound rules on PrivateLink traffic" is on by default for NLB security groups - the inbound rule must cover Atlan's CIDR.
3. **(Recommended) Close the public path** once the private one is verified: tighten rules permitting TCP 1433 from `0.0.0.0/0`.

## Phase 5 - Connect and verify

**Owner:** Atlan User

1. In the crawler setup, enter the **endpoint DNS name** from Phase 3 in the **Host** field - not the PLS alias / service name, and not the server's public hostname (unless support confirms they've mapped your real hostname to the endpoint in DNS - ask, don't assume).
2. Enter the port, database, and credentials, then click **Test Authentication**.

## Success checklist

- Connection state shows **Approved** on your side
- Load balancer target/probe shows **Healthy** (VM/EC2/RDS variants)
- **Test Authentication** passes in Atlan
- Preflight checks pass and a small crawl completes

Any step failing - see [Troubleshooting SQL Server connectivity](https://docs.atlan.com/llms/connectors/microsoft-sql-server/troubleshooting-microsoft-sql-server-connectivity/llms.txt), which walks the private-link checks in root-cause order.

_Last updated: 27 August 2026._

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