diff --git a/app/bot.php b/app/bot.php
index 5cfaa4f..0bbc9b1 100644
--- a/app/bot.php
+++ b/app/bot.php
@@ -743,7 +743,7 @@ class Bot
             case 'letsencrypt':
                 $out[] = 'Install certificate:';
                 $this->update($this->input['chat'], $this->input['message_id'], implode("\n", $out));
-                exec("certbot certonly -n --agree-tos --email mail@{$conf['domain']} -d {$conf['domain']} --webroot -w /certs/ 2>&1", $out, $code);
+                exec("certbot certonly --preferred-chain 'ISRG Root X1' -n --agree-tos --email mail@{$conf['domain']} -d {$conf['domain']} --webroot -w /certs/ 2>&1", $out, $code);
                 if ($code > 0) {
                     $this->send($this->input['chat'], "ERROR\n" . implode("\n", $out));
                     break;
diff --git a/scripts/dns_close_53_port.sh b/scripts/dns_close_53_port.sh
new file mode 100644
index 0000000..ea175d4
--- /dev/null
+++ b/scripts/dns_close_53_port.sh
@@ -0,0 +1,5 @@
+make d
+rm /etc/systemd/resolved.conf.d/adguardhome.conf
+mv /etc/resolv.conf.backup /etc/resolv.conf
+systemctl reload-or-restart systemd-resolved
+make u
diff --git a/scripts/dns_open_53_port.sh b/scripts/dns_open_53_port.sh
new file mode 100644
index 0000000..785e6bd
--- /dev/null
+++ b/scripts/dns_open_53_port.sh
@@ -0,0 +1,8 @@
+mkdir /etc/systemd/resolved.conf.d
+echo "[Resolve]
+DNS=127.0.0.1
+DNSStubListener=no" > /etc/systemd/resolved.conf.d/adguardhome.conf
+mv /etc/resolv.conf /etc/resolv.conf.backup
+ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
+systemctl reload-or-restart systemd-resolved
+make d u