diff --git a/packages/instrumentation-undici/test/fetch.test.ts b/packages/instrumentation-undici/test/fetch.test.ts
index 7e389838bb..7496f860de 100644
--- a/packages/instrumentation-undici/test/fetch.test.ts
+++ b/packages/instrumentation-undici/test/fetch.test.ts
@@ -64,6 +64,11 @@ describe('UndiciInstrumentation `fetch` tests', function () {
     );
     mockServer.start(done);
     mockServer.mockListener((req, res) => {
+      if (req.url === '/error') {
+        // Simulate an error
+        res.destroy();
+        return;
+      }
       // There are some situations where there is no way to access headers
       // for trace propagation asserts like:
       // const resp = await fetch('http://host:port')
@@ -364,7 +369,7 @@ describe('UndiciInstrumentation `fetch` tests', function () {
 
       let fetchError;
       try {
-        const fetchUrl = 'http://unexistent-host-name/path';
+        const fetchUrl = `${protocol}://${hostname}:${mockServer.port}/error`;
         await fetch(fetchUrl);
       } catch (err) {
         // Expected error
@@ -376,14 +381,14 @@ describe('UndiciInstrumentation `fetch` tests', function () {
       assert.ok(span, 'a span is present');
       assert.strictEqual(spans.length, 1);
       assertSpan(span, {
-        hostname: 'unexistent-host-name',
+        hostname,
         httpMethod: 'GET',
-        path: '/path',
+        path: '/error',
         error: fetchError,
         noNetPeer: true, // do not check network attribs
         forceStatus: {
           code: SpanStatusCode.ERROR,
-          message: 'getaddrinfo ENOTFOUND unexistent-host-name',
+          message: 'other side closed',
         },
       });
     });
@@ -405,7 +410,7 @@ describe('UndiciInstrumentation `fetch` tests', function () {
       }
 
       // Let the error be published to diagnostics channel
-      await new Promise(r => setTimeout(r, 5));
+      await new Promise(r => setTimeout(r, 50));
 
       spans = memoryExporter.getFinishedSpans();
       const span = spans[0];
diff --git a/packages/instrumentation-undici/test/metrics.test.ts b/packages/instrumentation-undici/test/metrics.test.ts
index bca94ac6e9..5a4dd16048 100644
--- a/packages/instrumentation-undici/test/metrics.test.ts
+++ b/packages/instrumentation-undici/test/metrics.test.ts
@@ -63,6 +63,11 @@ describe('UndiciInstrumentation metrics tests', function () {
     );
     mockServer.start(done);
     mockServer.mockListener((req, res) => {
+      if (req.url === '/error') {
+        // Simulate an error
+        res.destroy();
+        return;
+      }
       // Return a valid response always
       res.statusCode = 200;
       res.setHeader('content-type', 'application/json');
@@ -143,7 +148,7 @@ describe('UndiciInstrumentation metrics tests', function () {
     });
 
     it('should have error.type in "http.client.request.duration" metric', async () => {
-      const fetchUrl = 'http://unknownhost/';
+      const fetchUrl = `${protocol}://${hostname}:${mockServer.port}/error`;
 
       try {
         await fetch(fetchUrl);
@@ -181,9 +186,12 @@ describe('UndiciInstrumentation metrics tests', function () {
       );
       assert.strictEqual(
         metricAttributes[SemanticAttributes.SERVER_ADDRESS],
-        'unknownhost'
+        hostname
+      );
+      assert.strictEqual(
+        metricAttributes[SemanticAttributes.SERVER_PORT],
+        mockServer.port
       );
-      assert.strictEqual(metricAttributes[SemanticAttributes.SERVER_PORT], 80);
       assert.ok(
         metricAttributes[SemanticAttributes.ERROR_TYPE],
         `the metric contains "${SemanticAttributes.ERROR_TYPE}" attribute if request failed`
diff --git a/packages/instrumentation-undici/test/undici.test.ts b/packages/instrumentation-undici/test/undici.test.ts
index 2a124fb199..26e391f32a 100644
--- a/packages/instrumentation-undici/test/undici.test.ts
+++ b/packages/instrumentation-undici/test/undici.test.ts
@@ -90,6 +90,11 @@ describe('UndiciInstrumentation `undici` tests', function () {
     );
     mockServer.start(done);
     mockServer.mockListener((req, res) => {
+      if (req.url === '/error') {
+        // Simulate an error
+        res.destroy();
+        return;
+      }
       // There are some situations where there is no way to access headers
       // for trace propagation asserts like:
       // const resp = await fetch('http://host:port')
@@ -727,7 +732,7 @@ describe('UndiciInstrumentation `undici` tests', function () {
 
       let fetchError;
       try {
-        const requestUrl = 'http://unexistent-host-name/path';
+        const requestUrl = `${protocol}://${hostname}:${mockServer.port}/error`;
         await undici.request(requestUrl);
       } catch (err) {
         // Expected error
@@ -739,14 +744,14 @@ describe('UndiciInstrumentation `undici` tests', function () {
       assert.ok(span, 'a span is present');
       assert.strictEqual(spans.length, 1);
       assertSpan(span, {
-        hostname: 'unexistent-host-name',
+        hostname,
         httpMethod: 'GET',
-        path: '/path',
+        path: '/error',
         error: fetchError,
         noNetPeer: true, // do not check network attribs
         forceStatus: {
           code: SpanStatusCode.ERROR,
-          message: 'getaddrinfo ENOTFOUND unexistent-host-name',
+          message: 'other side closed',
         },
       });
     });
@@ -777,7 +782,7 @@ describe('UndiciInstrumentation `undici` tests', function () {
       }
 
       // Let the error be published to diagnostics channel
-      await new Promise(r => setTimeout(r, 5));
+      await new Promise(r => setTimeout(r, 50));
 
       spans = memoryExporter.getFinishedSpans();
       const span = spans[0];