node: fix listening on IPv6 address (#27628) (#27635)

cmd/utils/flags.go

@@ -26,6 +26,7 @@ import (
 	"fmt"
 	"math"
 	"math/big"
+	"net"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -2014,7 +2015,7 @@ func SetupMetrics(ctx *cli.Context) {
 		}
 
 		if ctx.IsSet(MetricsHTTPFlag.Name) {
-			address := fmt.Sprintf("%s:%d", ctx.String(MetricsHTTPFlag.Name), ctx.Int(MetricsPortFlag.Name))
+			address := net.JoinHostPort(ctx.String(MetricsHTTPFlag.Name), fmt.Sprintf("%d", ctx.Int(MetricsPortFlag.Name)))
 			log.Info("Enabling stand-alone metrics HTTP endpoint", "address", address)
 			exp.Setup(address)
 		} else if ctx.IsSet(MetricsPortFlag.Name) {