diff --git a/modules/mssql/client.ts b/modules/mssql/client.ts
index a17998b..2fbb208 100644
--- a/modules/mssql/client.ts
+++ b/modules/mssql/client.ts
@@ -11,6 +11,7 @@
 // Structured rows still come back as JSON rendered by SQL Server itself (`FOR JSON`), so a tool's
 // answer is shaped exactly as it was: SQL Server owns the quoting and typing.
 
+import { isIP } from "node:net";
 import { randomBytes } from "node:crypto";
 import { readFileSync } from "node:fs";
 import sql from "mssql";
@@ -45,7 +46,10 @@ export const connectWithDriver: Connect = async (to) => {
     user: to.user,
     password: to.password,
     database: to.database,
-    options: { encrypt: true, trustServerCertificate: true },
+    // TLS names a host, never an address: Node refuses an IP as the server name (DEP0123, an error
+    // since Node 25), and the module reaches its server on loopback. The certificate is trusted
+    // either way, so the name only has to be one TLS accepts.
+    options: { encrypt: true, trustServerCertificate: true, ...(isIP(to.host) ? { serverName: "localhost" } : {}) },
     pool: { min: 0, max: 1 },
     connectionTimeout: 15_000,
     requestTimeout: 60_000,
diff --git a/modules/mssql/mssql.d.ts b/modules/mssql/mssql.d.ts
index d58a508..bcf3e41 100644
--- a/modules/mssql/mssql.d.ts
+++ b/modules/mssql/mssql.d.ts
@@ -18,7 +18,7 @@ declare module "mssql" {
       user?: string;
       password?: string;
       database?: string;
-      options?: { encrypt?: boolean; trustServerCertificate?: boolean };
+      options?: { encrypt?: boolean; trustServerCertificate?: boolean; serverName?: string };
       pool?: { min?: number; max?: number };
       connectionTimeout?: number;
       requestTimeout?: number;