client.go            | 16 ++++++++++++----
 config.go            |  1 +
 fs/torrentfs_test.go |  5 +++++

diff --git a/client.go b/client.go
index e5466e22231b44e5d02f486f42d65e55f80be3fa..58458087e2f081186053aefd4ae7c6764129d2ee 100644
--- a/client.go
+++ b/client.go
@@ -134,6 +134,10 @@
 	dataWaits map[*torrent][]dataWait
 }
 
+func (me *Client) PeerID() string {
+	return string(me.peerID[:])
+}
+
 func (me *Client) ListenAddr() (addr net.Addr) {
 	for _, l := range me.listeners {
 		if addr != nil && l.Addr().String() != addr.String() {
@@ -260,10 +264,14 @@ 	}
 	cl.event.L = &cl.mu
 	cl.mu.Init(2)
 
-	o := copy(cl.peerID[:], BEP20)
-	_, err = rand.Read(cl.peerID[o:])
-	if err != nil {
-		panic("error generating peer id")
+	if cfg.PeerID != "" {
+		CopyExact(&cl.peerID, cfg.PeerID)
+	} else {
+		o := copy(cl.peerID[:], BEP20)
+		_, err = rand.Read(cl.peerID[o:])
+		if err != nil {
+			panic("error generating peer id")
+		}
 	}
 
 	if cl.downloadStrategy == nil {
diff --git a/config.go b/config.go
index 6f954bc5d93591258b64f34a082b3005580f47d5..3b3b08378ff4ccab15ade5b3edfc3e5a8c169f96 100644
--- a/config.go
+++ b/config.go
@@ -7,4 +7,5 @@ 	DisableTrackers  bool
 	DownloadStrategy DownloadStrategy
 	NoDHT            bool
 	NoUpload         bool
+	PeerID           string
 }
diff --git a/fs/torrentfs_test.go b/fs/torrentfs_test.go
index 45e75acf25b51ced90d596b5b37fa601150b2d9a..8c48a00601603cf53012f93e08c1c4432380da87 100644
--- a/fs/torrentfs_test.go
+++ b/fs/torrentfs_test.go
@@ -152,6 +152,11 @@ 		DataDir:          filepath.Join(layout.BaseDir, "download"),
 		DownloadStrategy: torrent.NewResponsiveDownloadStrategy(0),
 		DisableTrackers:  true,
 		NoDHT:            true,
+
+		// This can be used to check if clients can connect to other clients
+		// with the same ID.
+
+		// PeerID: seeder.PeerID(),
 	})
 	http.HandleFunc("/leecher", func(w http.ResponseWriter, req *http.Request) {
 		leecher.WriteStatus(w)