diff --git a/src/acme.rs b/src/acme.rs
index 28d4a20..4aed16b 100644
--- a/src/acme.rs
+++ b/src/acme.rs
@@ -1,9 +1,8 @@
+use std::fs;
 use std::sync::RwLock;
 use std::collections::BTreeMap;
-use std::fs;
-use acme_lib::{create_p256_key, create_p384_key, create_rsa_key};
+use acme_lib::{Directory, create_p256_key, create_p384_key, create_rsa_key};
 use acme_lib::persist::FilePersist;
-use acme_lib::Directory;
 use rust_util::XResult;
 use aliyun_openapi_core_rust_sdk::RPClient;
 use crate::util::parse_dns_record;
diff --git a/src/config.rs b/src/config.rs
index 3ba5912..72c1278 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,13 +1,12 @@
-use std::collections::HashMap;
-use serde::{Deserialize, Serialize};
-use rust_util::XResult;
 use std::fs;
-use acme_lib::DirectoryUrl;
+use std::collections::HashMap;
 use std::path::PathBuf;
 use std::str::FromStr;
 use std::time::SystemTime;
-use crate::x509;
-use crate::x509::{X509PublicKeyAlgo, X509Certificate};
+use serde::{Deserialize, Serialize};
+use rust_util::XResult;
+use acme_lib::DirectoryUrl;
+use crate::x509::{X509PublicKeyAlgo, X509Certificate, parse_x509};
 
 pub const CERT_NAME: &str = "cert.pem";
 pub const KEY_NAME: &str = "key.pem";
@@ -157,7 +156,7 @@ impl CertConfigItem {
         let cert_path_buff = path_buff.join(CERT_NAME);
         if self.common_name.is_none() && self.dns_names.is_none() {
             let pem = opt_result!(fs::read_to_string(cert_path_buff.clone()), "Read file: {:?}, failed: {}", cert_path_buff);
-            let x509_certificate = opt_result!(x509::parse_x509(&format!("{}/{}", self.path, CERT_NAME), &pem), "Parse x509: {}/{}, faield: {}", self.path, CERT_NAME);
+            let x509_certificate = opt_result!(parse_x509(&format!("{}/{}", self.path, CERT_NAME), &pem), "Parse x509: {}/{}, faield: {}", self.path, CERT_NAME);
             self.common_name = Some(x509_certificate.common_name.clone());
             self.dns_names = Some(x509_certificate.alt_names.clone());
             if let Some(pos) = x509_certificate.alt_names.iter().position(|n| n == &x509_certificate.common_name) {
@@ -185,7 +184,7 @@ impl CertConfigItem {
             }
             if cert_path_buff.exists() {
                 let pem = opt_result!(fs::read_to_string(cert_path_buff.clone()), "Read file: {:?}, failed: {}", cert_path_buff);
-                let x509_certificate = opt_result!(x509::parse_x509(&format!("{}/{}", self.path, CERT_NAME), &pem), "Parse x509: {}/{}, faield: {}", self.path, CERT_NAME);
+                let x509_certificate = opt_result!(parse_x509(&format!("{}/{}", self.path, CERT_NAME), &pem), "Parse x509: {}/{}, faield: {}", self.path, CERT_NAME);
 
                 let mut self_dns_names = vec![];
                 let mut cert_dns_names = vec![];
diff --git a/src/main.rs b/src/main.rs
index ab37ad6..64e4514 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,14 +13,14 @@ mod dingtalk;
 mod ali_dns;
 // mod simple_thread_pool;
 
-use std::env;
-use clap::{App, Arg};
 use std::fs;
-use std::str::FromStr;
-use tide::Request;
+use std::env;
+use std::path::PathBuf;
 use std::process::{Command, exit};
 use std::time::{Duration, SystemTime};
-use std::path::PathBuf;
+use std::str::FromStr;
+use tide::Request;
+use clap::{App, Arg};
 use async_std::task;
 use async_std::channel;
 use async_std::channel::Sender;
diff --git a/src/util.rs b/src/util.rs
index 590ef88..ab9e6a5 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,5 +1,7 @@
 use rust_util::XResult;
 
+// "example.com" -> ("@", "example.com")
+// "www.example.com" -> ("www", "example.com")
 pub fn parse_dns_record(record: &str) -> XResult<(String, String)> {
     let r = if record.ends_with(".") {
         record.chars().take(record.len() - 1).collect::<String>().to_ascii_lowercase()
@@ -18,7 +20,7 @@ pub fn parse_dns_record(record: &str) -> XResult<(String, String)> {
     // SHOULD read from: https://publicsuffix.org/
     let domain_parts_len = match last_part {
         "cn" => match last_part_2 {
-            "com" | "net" | "org" | "gov" => 3,
+            "com" | "net" | "org" | "gov" | "edu" => 3,
             _ => 2,
         },
         _ => 2,