diff --git a/dns/dns.go b/dns/dns.go
index b8d177f..c51bcba 100644
--- a/dns/dns.go
+++ b/dns/dns.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/fumiama/terasu"
 	"github.com/fumiama/terasu/ip"
+	"github.com/sirupsen/logrus"
 )
 
 var (
@@ -163,6 +164,7 @@ func (ds *DNSList) DialContext(ctx context.Context, dialer *net.Dialer, firstFra
 			if !addr.e || strings.HasPrefix(addr.a, "https://") { // disabled or is DoH
 				continue
 			}
+			logrus.Debugln("[terasu.dns] start dial", host, addr)
 			if dialer.Timeout != 0 {
 				var cancel context.CancelFunc
 				ctx, cancel = context.WithTimeout(context.Background(), dialer.Timeout)
@@ -174,24 +176,29 @@ func (ds *DNSList) DialContext(ctx context.Context, dialer *net.Dialer, firstFra
 			}
 			conn, err = dialer.DialContext(ctx, "tcp", addr.a)
 			if err != nil {
+				logrus.Debugln("[terasu.dns] dial tcp", host, addr, "err:", err)
 				if !errors.Is(err, context.DeadlineExceeded) && !errors.Is(err, context.Canceled) {
 					addr.disable(time.Hour) // no need to acquire write lock
 				}
 				continue
 			}
+			logrus.Debugln("[terasu.dns] start hs tls", host, addr)
 			tlsConn = tls.Client(conn, &tls.Config{
 				ServerName: host,
 				MinVersion: tls.VersionTLS12,
 				NextProtos: []string{"dns"},
 			})
 			if firstFragmentLen > 0 {
+				logrus.Debugln("[terasu.dns] hs tls", host, addr, "use first frag len", firstFragmentLen)
 				err = terasu.Use(tlsConn).HandshakeContext(ctx, firstFragmentLen)
 			} else {
+				logrus.Debugln("[terasu.dns] hs tls", host, addr, "normally")
 				err = tlsConn.HandshakeContext(ctx)
 			}
 			if err == nil {
 				return nil
 			}
+			logrus.Debugln("[terasu.dns] hs tls", host, addr, "err:", err)
 			_ = tlsConn.Close()
 			if !errors.Is(err, context.DeadlineExceeded) && !errors.Is(err, context.Canceled) {
 				addr.disable(time.Hour) // no need to acquire write lock
diff --git a/go.mod b/go.mod
index 477cfb4..1308bd0 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,11 @@ go 1.20
 
 require (
 	github.com/FloatTech/ttl v0.0.0-20250224045156-012b1463287d
+	github.com/sirupsen/logrus v1.9.3
 	golang.org/x/net v0.24.0
 )
 
-require golang.org/x/text v0.14.0 // indirect
+require (
+	golang.org/x/sys v0.19.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+)
diff --git a/go.sum b/go.sum
index d19112b..6d0797c 100644
--- a/go.sum
+++ b/go.sum
@@ -1,10 +1,22 @@
 github.com/FloatTech/ttl v0.0.0-20250224045156-012b1463287d h1:mUQ/c3wXKsUGa4Sg9DBy01APXKB68PmobhxOyaJI7lY=
 github.com/FloatTech/ttl v0.0.0-20250224045156-012b1463287d/go.mod h1:fHZFWGquNXuHttu9dUYoKuNbm3dzLETnIOnm1muSfDs=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
+github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 golang.org/x/net v0.24.0 h1:1PcaxkF854Fu3+lvBIx5SYn9wRlBzzcnHZSiaFFAb0w=
 golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
+golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=