diff --git a/mailserver/mailserver.go b/mailserver/mailserver.go
index a402f1f71..ad2369f9c 100644
--- a/mailserver/mailserver.go
+++ b/mailserver/mailserver.go
@@ -240,7 +240,7 @@ func (s *WMailServer) Archive(env *whisper.Envelope) {
 
 // DeliverMail sends mail to specified whisper peer.
 func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope) {
-	log.Info("Delivering mail", "peer", peer.ID())
+	log.Info("Delivering mail", "peerID", peerIDString(peer))
 	requestsMeter.Mark(1)
 
 	if peer == nil {
@@ -250,7 +250,7 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 	}
 	if s.exceedsPeerRequests(peer.ID()) {
 		requestErrorsCounter.Inc(1)
-		log.Error("Peer exceeded request per seconds limit", "peerID", peer.ID())
+		log.Error("Peer exceeded request per seconds limit", "peerID", peerIDString(peer))
 		s.trySendHistoricMessageErrorResponse(peer, request, fmt.Errorf("rate limit exceeded"))
 		return
 	}
@@ -274,13 +274,13 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 		limit = payload.Limit
 		batch = payload.Batch
 	} else {
-		log.Debug("Failed to decode request", "err", err, "peerID", peer.ID())
+		log.Debug("Failed to decode request", "err", err, "peerID", peerIDString(peer))
 		lower, upper, bloom, limit, cursor, err = s.validateRequest(peer.ID(), request)
 	}
 
 	if err != nil {
 		requestValidationErrorsCounter.Inc(1)
-		log.Error("Mailserver request failed validaton", "peerID", peer.ID())
+		log.Error("Mailserver request failed validaton", "peerID", peerIDString(peer))
 		s.trySendHistoricMessageErrorResponse(peer, request, err)
 		return
 	}
@@ -301,7 +301,7 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 		batch)
 	if err != nil {
 		processRequestErrorsCounter.Inc(1)
-		log.Error("Error while processing mail server request", "err", err, "peerID", peer.ID())
+		log.Error("Error while processing mail server request", "err", err, "peerID", peerIDString(peer))
 		s.trySendHistoricMessageErrorResponse(peer, request, err)
 		return
 	}
@@ -310,7 +310,7 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 
 	if err := s.sendHistoricMessageResponse(peer, request, lastEnvelopeHash, nextPageCursor); err != nil {
 		historicResponseErrorsCounter.Inc(1)
-		log.Error("Error sending historic message response", "err", err, "peerID", peer.ID())
+		log.Error("Error sending historic message response", "err", err, "peerID", peerIDString(peer))
 		// we still want to try to report error even it it is a p2p error and it is unlikely
 		s.trySendHistoricMessageErrorResponse(peer, request, err)
 	}
@@ -497,7 +497,7 @@ func (s *WMailServer) trySendHistoricMessageErrorResponse(peer *whisper.Peer, re
 	// if we can't report an error, probably something is wrong with p2p connection,
 	// so we just print a log entry to document this sad fact
 	if err != nil {
-		log.Error("Error while reporting error response", "err", err, "peerID", peer.ID())
+		log.Error("Error while reporting error response", "err", err, "peerID", peerIDString(peer))
 	}
 }
 
@@ -547,7 +547,7 @@ func (s *WMailServer) decodeRequest(peerID []byte, request *whisper.Envelope) (s
 	lowerTime := time.Unix(int64(payload.Lower), 0)
 	upperTime := time.Unix(int64(payload.Upper), 0)
 	if upperTime.Sub(lowerTime) > maxQueryRange {
-		log.Warn("Query range too long", "peerID", peerID, "length", upperTime.Sub(lowerTime), "max", maxQueryRange)
+		log.Warn("Query range too long", "peerID", peerIDBytesString(peerID), "length", upperTime.Sub(lowerTime), "max", maxQueryRange)
 		return payload, fmt.Errorf("query range must be shorted than %d", maxQueryRange)
 	}
 
@@ -638,3 +638,19 @@ func (s *WMailServer) bloomFromReceivedMessage(msg *whisper.ReceivedMessage) ([]
 
 	return msg.Payload[8 : 8+whisper.BloomFilterSize], nil
 }
+
+// peerWithID is a generalization of whisper.Peer.
+// whisper.Peer has all fields and methods, except for ID(), unexported.
+// It makes it impossible to create an instance of it
+// outside of whisper package and test properly.
+type peerWithID interface {
+	ID() []byte
+}
+
+func peerIDString(peer peerWithID) string {
+	return fmt.Sprintf("%x", peer.ID())
+}
+
+func peerIDBytesString(id []byte) string {
+	return fmt.Sprintf("%x", id)
+}
diff --git a/mailserver/mailserver_test.go b/mailserver/mailserver_test.go
index d6ccf3092..74a8a497d 100644
--- a/mailserver/mailserver_test.go
+++ b/mailserver/mailserver_test.go
@@ -27,6 +27,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -637,3 +639,16 @@ func generateEnvelope(sentTime time.Time) (*whisper.Envelope, error) {
 	h := crypto.Keccak256Hash([]byte("test sample data"))
 	return generateEnvelopeWithKeys(sentTime, h[:], nil)
 }
+
+// mockPeerWithID is a struct that conforms to peerWithID interface.
+type mockPeerWithID struct {
+	id []byte
+}
+
+func (p mockPeerWithID) ID() []byte { return p.id }
+
+func TestPeerIDString(t *testing.T) {
+	a := []byte{0x01, 0x02, 0x03}
+	require.Equal(t, "010203", peerIDString(&mockPeerWithID{a}))
+	require.Equal(t, "010203", peerIDBytesString(a))
+}