tracker/client.go          |  3 +++
 tracker/tracker.go         |  4 ++++
 tracker/udp/conn-client.go | 26 ++++++++++++++++++--------
 tracker/udp/udp_test.go    | 18 ++++++++++++++++++
 tracker_scraper.go         |  1 +

diff --git a/tracker/client.go b/tracker/client.go
index ee444e2b49c2ec5825dc704ebce49fd409ebd2d3..1df0aa430aa29aa82d71858346f88f70148839b1 100644
--- a/tracker/client.go
+++ b/tracker/client.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"net/url"
 
+	"github.com/anacrolix/log"
 	trHttp "github.com/anacrolix/torrent/tracker/http"
 	"github.com/anacrolix/torrent/tracker/udp"
 )
@@ -19,6 +20,7 @@ type NewClientOpts struct {
 	Http trHttp.NewClientOpts
 	// Overrides the network in the scheme. Probably a legacy thing.
 	UdpNetwork string
+	Logger     log.Logger
 }
 
 func NewClient(urlStr string, opts NewClientOpts) (Client, error) {
@@ -37,6 +39,7 @@ 		}
 		cc, err := udp.NewConnClient(udp.NewConnClientOpts{
 			Network: network,
 			Host:    _url.Host,
+			Logger:  opts.Logger,
 		})
 		if err != nil {
 			return nil, err
diff --git a/tracker/tracker.go b/tracker/tracker.go
index f058f63bb2a13d451ebda091d21126b3d0b8cb67..7c3a5f6dd4b5394e720df31c92b1a702c9c00a62 100644
--- a/tracker/tracker.go
+++ b/tracker/tracker.go
@@ -3,11 +3,13 @@
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/http"
 	"net/url"
 	"time"
 
 	"github.com/anacrolix/dht/v2/krpc"
+	"github.com/anacrolix/log"
 	trHttp "github.com/anacrolix/torrent/tracker/http"
 	"github.com/anacrolix/torrent/tracker/shared"
 	"github.com/anacrolix/torrent/tracker/udp"
@@ -43,6 +45,7 @@ 	ClientIp4 krpc.NodeAddr
 	// If the port is zero, it's assumed to be the same as the Request.Port.
 	ClientIp6 krpc.NodeAddr
 	Context   context.Context
+	Logger    log.Logger
 }
 
 // The code *is* the documentation.
@@ -55,6 +58,7 @@ 			Proxy:      me.HTTPProxy,
 			ServerName: me.ServerName,
 		},
 		UdpNetwork: me.UdpNetwork,
+		Logger:     me.Logger.WithContextValue(fmt.Sprintf("tracker client for %q", me.TrackerUrl)),
 	})
 	if err != nil {
 		return
diff --git a/tracker/udp/conn-client.go b/tracker/udp/conn-client.go
index 1958c65953359558fd18dff4bddbbd9ed0155b62..f07ae69c0139b31f0c6d5017328a40d50e73fd70 100644
--- a/tracker/udp/conn-client.go
+++ b/tracker/udp/conn-client.go
@@ -2,8 +2,9 @@ package udp
 
 import (
 	"context"
-	"log"
 	"net"
+
+	"github.com/anacrolix/log"
 
 	"github.com/anacrolix/missinggo/v2"
 )
@@ -15,6 +16,8 @@ 	// Tracker address
 	Host string
 	// If non-nil, forces either IPv4 or IPv6 in the UDP tracker wire protocol.
 	Ipv6 *bool
+	// Logger to use for internal errors.
+	Logger log.Logger
 }
 
 // Manages a Client with a specific connection.
@@ -42,7 +45,7 @@ 			break
 		}
 		err = cc.d.Dispatch(b[:n], addr)
 		if err != nil {
-			log.Printf("dispatching packet received on %v: %v", cc.conn.LocalAddr(), err)
+			cc.newOpts.Logger.WithLevel(log.Debug).Printf("dispatching packet received on %v: %v", cc.conn.LocalAddr(), err)
 		}
 	}
 }
@@ -81,6 +84,9 @@ 	conn, err := net.ListenPacket(opts.Network, ":0")
 	if err != nil {
 		return
 	}
+	if opts.Logger.IsZero() {
+		opts.Logger = log.Default
+	}
 	cc = &ConnClient{
 		Client: Client{
 			Writer: clientWriter{
@@ -97,17 +103,21 @@ 	go cc.reader()
 	return
 }
 
-func (c *ConnClient) Close() error {
-	c.closed = true
-	return c.conn.Close()
+func (cc *ConnClient) Close() error {
+	cc.closed = true
+	return cc.conn.Close()
 }
 
-func (c *ConnClient) Announce(
+func (cc *ConnClient) Announce(
 	ctx context.Context, req AnnounceRequest, opts Options,
 ) (
 	h AnnounceResponseHeader, nas AnnounceResponsePeers, err error,
 ) {
-	return c.Client.Announce(ctx, req, opts, func(addr net.Addr) bool {
-		return ipv6(c.newOpts.Ipv6, c.newOpts.Network, addr)
+	return cc.Client.Announce(ctx, req, opts, func(addr net.Addr) bool {
+		return ipv6(cc.newOpts.Ipv6, cc.newOpts.Network, addr)
 	})
 }
+
+func (cc *ConnClient) LocalAddr() net.Addr {
+	return cc.conn.LocalAddr()
+}
diff --git a/tracker/udp/udp_test.go b/tracker/udp/udp_test.go
index 862aec73d572d0ebd0e360a674ed7b6c033e04a8..cbb41778bd4368d3b87d3a97eb577c4c865d9cb1 100644
--- a/tracker/udp/udp_test.go
+++ b/tracker/udp/udp_test.go
@@ -8,6 +8,7 @@ 	"net"
 	"testing"
 
 	"github.com/anacrolix/dht/v2/krpc"
+	qt "github.com/frankban/quicktest"
 	"github.com/stretchr/testify/require"
 )
 
@@ -73,3 +74,20 @@ 	if int(uint16(int16(i))) != 50000 {
 		t.FailNow()
 	}
 }
+
+func TestConnClientLogDispatchUnknownTransactionId(t *testing.T) {
+	const network = "udp"
+	cc, err := NewConnClient(NewConnClientOpts{
+		Network: network,
+	})
+	c := qt.New(t)
+	c.Assert(err, qt.IsNil)
+	defer cc.Close()
+	pc, err := net.ListenPacket(network, ":0")
+	c.Assert(err, qt.IsNil)
+	defer pc.Close()
+	ccAddr := *cc.LocalAddr().(*net.UDPAddr)
+	ccAddr.IP = net.IPv6loopback
+	_, err = pc.WriteTo(make([]byte, 30), &ccAddr)
+	c.Assert(err, qt.IsNil)
+}
diff --git a/tracker_scraper.go b/tracker_scraper.go
index 93b3ebcab07127f0722bc406fc10ca3115a8e643..b441efb9e7028010a919a63a324383ba53304629 100644
--- a/tracker_scraper.go
+++ b/tracker_scraper.go
@@ -166,6 +166,7 @@ 		ServerName: me.u.Hostname(),
 		UdpNetwork: me.u.Scheme,
 		ClientIp4:  krpc.NodeAddr{IP: me.t.cl.config.PublicIp4},
 		ClientIp6:  krpc.NodeAddr{IP: me.t.cl.config.PublicIp6},
+		Logger:     me.t.logger,
 	}.Do()
 	me.t.logger.WithDefaultLevel(log.Debug).Printf("announce to %q returned %#v: %v", me.u.String(), res, err)
 	if err != nil {