Bump default idleConnsPerHost to control conns in time_wait (#10653)

This PR fixes a hang which occurs quite commonly at higher concurrency
by allowing following changes

- allowing lower connections in time_wait allows faster socket open's
- lower idle connection timeout to ensure that we let kernel
  reclaim the time_wait connections quickly
- increase somaxconn to 4096 instead of 2048 to allow larger tcp
  syn backlogs.

fixes #10413

cmd/auth-handler.go

@@ -334,7 +334,8 @@ func checkRequestAuthTypeToAccessKey(ctx context.Context, r *http.Request, actio
 		r.Body = ioutil.NopCloser(bytes.NewReader(payload))
 	}
 
-	if cred.AccessKey == "" {
+	if action != policy.ListAllMyBucketsAction && cred.AccessKey == "" {
+		// Anonymous checks are not meant for ListBuckets action
 		if globalPolicySys.IsAllowed(policy.Args{
 			AccountName:     cred.AccessKey,
 			Action:          action,
@@ -378,6 +379,7 @@ func checkRequestAuthTypeToAccessKey(ctx context.Context, r *http.Request, actio
 		// Request is allowed return the appropriate access key.
 		return cred.AccessKey, owner, ErrNone
 	}
+
 	if action == policy.ListBucketVersionsAction {
 		// In AWS S3 s3:ListBucket permission is same as s3:ListBucketVersions permission
 		// verify as a fallback.