diff --git a/integrationtests/self/conn_id_test.go b/integrationtests/self/conn_id_test.go
new file mode 100644
index 00000000..cfa9ec6d
--- /dev/null
+++ b/integrationtests/self/conn_id_test.go
@@ -0,0 +1,101 @@
+package self_test
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io/ioutil"
+	"math/rand"
+	"net"
+
+	quic "github.com/lucas-clemente/quic-go"
+	"github.com/lucas-clemente/quic-go/integrationtests/tools/testserver"
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/testdata"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Connection ID lengths tests", func() {
+	randomConnIDLen := func() int {
+		return 4 + int(rand.Int31n(15))
+	}
+
+	runServer := func(conf *quic.Config) quic.Listener {
+		GinkgoWriter.Write([]byte(fmt.Sprintf("Using %d byte connection ID for the server\n", conf.ConnectionIDLength)))
+		ln, err := quic.ListenAddr("localhost:0", testdata.GetTLSConfig(), conf)
+		Expect(err).ToNot(HaveOccurred())
+		go func() {
+			defer GinkgoRecover()
+			for {
+				sess, err := ln.Accept()
+				if err != nil {
+					return
+				}
+				go func() {
+					defer GinkgoRecover()
+					str, err := sess.OpenStream()
+					Expect(err).ToNot(HaveOccurred())
+					defer str.Close()
+					_, err = str.Write(testserver.PRData)
+					Expect(err).ToNot(HaveOccurred())
+				}()
+			}
+		}()
+		return ln
+	}
+
+	runClient := func(addr net.Addr, conf *quic.Config) {
+		GinkgoWriter.Write([]byte(fmt.Sprintf("Using %d byte connection ID for the client\n", conf.ConnectionIDLength)))
+		cl, err := quic.DialAddr(
+			fmt.Sprintf("quic.clemente.io:%d", addr.(*net.UDPAddr).Port),
+			&tls.Config{InsecureSkipVerify: true},
+			conf,
+		)
+		Expect(err).ToNot(HaveOccurred())
+		defer cl.Close(nil)
+		str, err := cl.AcceptStream()
+		Expect(err).ToNot(HaveOccurred())
+		data, err := ioutil.ReadAll(str)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(data).To(Equal(testserver.PRData))
+	}
+
+	Context("IETF QUIC", func() {
+		It("downloads a file using a 0-byte connection ID for the client", func() {
+			serverConf := &quic.Config{
+				ConnectionIDLength: randomConnIDLen(),
+				Versions:           []protocol.VersionNumber{protocol.VersionTLS},
+			}
+			clientConf := &quic.Config{
+				Versions: []protocol.VersionNumber{protocol.VersionTLS},
+			}
+
+			ln := runServer(serverConf)
+			defer ln.Close()
+			runClient(ln.Addr(), clientConf)
+		})
+
+		It("downloads a file when both client and server use a random connection ID length", func() {
+			serverConf := &quic.Config{
+				ConnectionIDLength: randomConnIDLen(),
+				Versions:           []protocol.VersionNumber{protocol.VersionTLS},
+			}
+			clientConf := &quic.Config{
+				ConnectionIDLength: randomConnIDLen(),
+				Versions:           []protocol.VersionNumber{protocol.VersionTLS},
+			}
+
+			ln := runServer(serverConf)
+			defer ln.Close()
+			runClient(ln.Addr(), clientConf)
+		})
+	})
+
+	Context("gQUIC", func() {
+		It("downloads a file using a 0-byte connection ID for the client", func() {
+			ln := runServer(&quic.Config{})
+			defer ln.Close()
+			runClient(ln.Addr(), &quic.Config{RequestConnectionIDOmission: true})
+		})
+	})
+})