diff --git a/internal/utils/ip.go b/internal/utils/ip.go
deleted file mode 100644
index 7ac7ffec..00000000
--- a/internal/utils/ip.go
+++ /dev/null
@@ -1,10 +0,0 @@
-package utils
-
-import "net"
-
-func IsIPv4(ip net.IP) bool {
-	// If ip is not an IPv4 address, To4 returns nil.
-	// Note that there might be some corner cases, where this is not correct.
-	// See https://stackoverflow.com/questions/22751035/golang-distinguish-ipv4-ipv6.
-	return ip.To4() != nil
-}
diff --git a/internal/utils/ip_test.go b/internal/utils/ip_test.go
deleted file mode 100644
index fdeec2e2..00000000
--- a/internal/utils/ip_test.go
+++ /dev/null
@@ -1,17 +0,0 @@
-package utils
-
-import (
-	"net"
-
-	. "github.com/onsi/ginkgo/v2"
-	. "github.com/onsi/gomega"
-)
-
-var _ = Describe("IP", func() {
-	It("tells IPv4 and IPv6 addresses apart", func() {
-		Expect(IsIPv4(net.IPv4(127, 0, 0, 1))).To(BeTrue())
-		Expect(IsIPv4(net.IPv4zero)).To(BeTrue())
-		Expect(IsIPv4(net.IPv6zero)).To(BeFalse())
-		Expect(IsIPv4(net.IPv6loopback)).To(BeFalse())
-	})
-})
diff --git a/qlog/event.go b/qlog/event.go
index 7602b55c..55fc3d5e 100644
--- a/qlog/event.go
+++ b/qlog/event.go
@@ -9,7 +9,6 @@ import (
 
 	"github.com/quic-go/quic-go"
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 	"github.com/quic-go/quic-go/logging"
 
 	"github.com/francoispqt/gojay"
@@ -72,7 +71,7 @@ func (e eventConnectionStarted) Name() string       { return "connection_started
 func (e eventConnectionStarted) IsNil() bool        { return false }
 
 func (e eventConnectionStarted) MarshalJSONObject(enc *gojay.Encoder) {
-	if utils.IsIPv4(e.SrcAddr.IP) {
+	if e.SrcAddr.IP.To4() != nil {
 		enc.StringKey("ip_version", "ipv4")
 	} else {
 		enc.StringKey("ip_version", "ipv6")
diff --git a/sys_conn_oob_test.go b/sys_conn_oob_test.go
index a24480ab..7fe74eff 100644
--- a/sys_conn_oob_test.go
+++ b/sys_conn_oob_test.go
@@ -11,7 +11,6 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
@@ -28,6 +27,8 @@ func (c *oobRecordingConn) WriteMsgUDP(b, oob []byte, addr *net.UDPAddr) (n, oob
 	return c.UDPConn.WriteMsgUDP(b, oob, addr)
 }
 
+func isIPv4(ip net.IP) bool { return ip.To4() != nil }
+
 var _ = Describe("OOB Conn Test", func() {
 	runServer := func(network, address string) (*net.UDPConn, <-chan receivedPacket) {
 		addr, err := net.ResolveUDPAddr(network, address)
@@ -123,7 +124,7 @@ var _ = Describe("OOB Conn Test", func() {
 
 			var p receivedPacket
 			Eventually(packetChan).Should(Receive(&p))
-			Expect(utils.IsIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeTrue())
+			Expect(isIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeTrue())
 			Expect(p.ecn).To(Equal(protocol.ECNCE))
 
 			// IPv6
@@ -136,7 +137,7 @@ var _ = Describe("OOB Conn Test", func() {
 			)
 
 			Eventually(packetChan).Should(Receive(&p))
-			Expect(utils.IsIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeFalse())
+			Expect(isIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeFalse())
 			Expect(p.ecn).To(Equal(protocol.ECT1))
 		})
 
@@ -233,7 +234,7 @@ var _ = Describe("OOB Conn Test", func() {
 
 			var p receivedPacket
 			Eventually(packetChan).Should(Receive(&p))
-			Expect(utils.IsIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeTrue())
+			Expect(isIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeTrue())
 			Expect(p.info).To(Not(BeNil()))
 			Expect(p.info.addr.Is4()).To(BeTrue())
 			ip := p.info.addr.As4()
@@ -244,7 +245,7 @@ var _ = Describe("OOB Conn Test", func() {
 			sendPacket("udp6", &net.UDPAddr{IP: net.IPv6loopback, Port: port})
 
 			Eventually(packetChan).Should(Receive(&p))
-			Expect(utils.IsIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeFalse())
+			Expect(isIPv4(p.remoteAddr.(*net.UDPAddr).IP)).To(BeFalse())
 			Expect(p.info).To(Not(BeNil()))
 			Expect(net.IP(p.info.addr.AsSlice())).To(Equal(ip6))
 		})