diff --git a/extras/sniff/sniff.go b/extras/sniff/sniff.go
index e0c94d4..b2d7419 100644
--- a/extras/sniff/sniff.go
+++ b/extras/sniff/sniff.go
@@ -112,11 +112,21 @@ func (h *Sniffer) TCP(stream quic.Stream, reqAddr *string) ([]byte, error) {
 		tr := &teeReader{Stream: stream, Pre: pre}
 		req, _ := http.ReadRequest(bufio.NewReader(tr))
 		if req != nil && req.Host != "" {
-			_, port, err := net.SplitHostPort(*reqAddr)
+			// req.Host may already contain the port.
+			// If it does, just overwrite the whole address with req.Host.
+			// Otherwise, use the port in reqAddr.
+			_, _, err := net.SplitHostPort(req.Host)
 			if err != nil {
-				return nil, err
+				// Not host:port format, append the port from reqAddr
+				_, port, err := net.SplitHostPort(*reqAddr)
+				if err != nil {
+					return nil, err
+				}
+				*reqAddr = net.JoinHostPort(req.Host, port)
+			} else {
+				// Already host:port format
+				*reqAddr = req.Host
 			}
-			*reqAddr = net.JoinHostPort(req.Host, port)
 		}
 		return tr.Buffer(), nil
 	} else if h.isTLS(pre) {