DNS on Ricky

Articles

Wed, 10 Jun 2026 10:59:53 +0800

Linux 系统误将 chmod 权限改成了 000，如何恢复?

#include <sys/stat.h>

int main() {
 chmod("/usr/bin/chmod", 0755);
 return 0;
}

ubuntu@ubuntu:~$ which chmod
/usr/bin/chmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
-rwxr-xr-x 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod
ubuntu@ubuntu:~$ sudo chmod 000 /usr/bin/chmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
---------- 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod
ubuntu@ubuntu:~$ cat main.c
#include <sys/stat.h>

int main() {
 chmod("/usr/bin/chmod", 0755);
 return 0;
}

ubuntu@ubuntu:~$ gcc ./main.c
ubuntu@ubuntu:~$ sudo ./a.out
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
-rwxr-xr-x 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod

Laptops all have built-in security tokens these days

macOS

https://github.com/yubico/libfido2

Mosdns-X

Sun, 09 Nov 2025 20:32:00 +0800

安裝

bash <(curl -sL https://raw.githubusercontent.com/lidebyte/bashshell/refs/heads/main/mosdns-x-manager.sh)

設定

sudo tee /etc/mosdns-x/config.yaml > /dev/null <<'EOF'
# mosdns-x 并发查询（无分流）配置

log:
 level: info
 file: /var/log/mosdns-x/mosdns-x.log

plugins:
 # 缓存插件
 - tag: cache
 type: cache
 args:
 size: 1024
 lazy_cache_ttl: 1800

 # 并发上游：取最先返回的可用答案
 - tag: forward_all
 type: fast_forward
 args:
 upstream:
 # 阿里
 - addr: "udp://223.5.5.5"
 - addr: "tls://dns.alidns.com"

 # DNSPod / doh.pub
 - addr: "udp://119.29.29.29"
 - addr: "tls://dot.pub"

 # Cloudflare
 - addr: "udp://1.1.1.1"
 - addr: "tls://cloudflare-dns.com"

 # Google
 - addr: "udp://8.8.8.8"
 - addr: "tls://dns.google"

 # 主流水线：小缓存 → 并发优选
 - tag: main
 type: sequence
 args:
 exec:
 - cache
 - forward_all

# 监听（双栈 UDP/TCP 53）
servers:
 - exec: main
 listeners:
 - addr: :53
 protocol: udp
 - addr: :53
 protocol: tcp
EOF

systemd

sudo tee /etc/systemd/system/mosdns.service > /dev/null <<'EOF'
[Unit]
Description=Mosdns-X DNS Accelerator
After=network.target

[Service]
Type=simple
User=root
Group=root
ExecStart=/usr/local/bin/mosdns-x start --as-service -d /usr/local/bin -c /etc/mosdns-x/config.yaml
Restart=always
RestartSec=5
StandardOutput=journal
StandardError=journal
SyslogIdentifier=mosdns

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl daemon-reload
sudo systemctl enable --now mosdns

# 备份系统 DNS
sudo cp -n /etc/resolv.conf /etc/resolv.conf.mosdns-backup

# 改为使用本地 Mosdns-X
echo -e "nameserver 127.0.0.1\noptions edns0" | sudo tee /etc/resolv.conf

# 若 53 端口被 systemd-resolved 占用，可禁用它
sudo systemctl disable --now systemd-resolved 2>/dev/null || true

# 如果想顺便加锁（防止被 DHCP 修改），加上 chattr 一起执行：
echo -e "nameserver 127.0.0.1\n" > /etc/resolv.conf && chattr +i /etc/resolv.conf

# 查看进程状态
sudo systemctl status mosdns --no-pager

# 测试解析速度（第二次命中缓存更快）
dig +stats www.google.com
dig +stats www.baidu.com

# 查看实时日志
tail -f /var/log/mosdns-x/mosdns-x.log

在瀏覽器輸入網址並送出後，到底發生了什麼事？

Sun, 18 Jul 2021 23:45:45 +0800

在瀏覽器輸入網址並送出後，到底發生了什麼事？

在 Ubuntu 22.04|20.04|18.04 安裝 PowerDNS 與 PowerDNS-Admin

Fri, 25 Sep 2020 09:38:17 +0800

安裝 PowerDNS

$ sudo apt update
$ sudo apt install mariadb-server -y

$ sudo mysql -u root

CREATE DATABASE powerdns;
GRANT ALL ON powerdns.* TO 'powerdns'@'localhost' IDENTIFIED BY 'Str0ngPasswOrd';
FLUSH PRIVILEGES;
USE powerdns;
CREATE TABLE domains (
 id INT AUTO_INCREMENT,
 name VARCHAR(255) NOT NULL,
 master VARCHAR(128) DEFAULT NULL,
 last_check INT DEFAULT NULL,
 type VARCHAR(6) NOT NULL,
 notified_serial INT UNSIGNED DEFAULT NULL,
 account VARCHAR(40) CHARACTER SET 'utf8' DEFAULT NULL,
 PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE UNIQUE INDEX name_index ON domains(name);


CREATE TABLE records (
 id BIGINT AUTO_INCREMENT,
 domain_id INT DEFAULT NULL,
 name VARCHAR(255) DEFAULT NULL,
 type VARCHAR(10) DEFAULT NULL,
 content VARCHAR(64000) DEFAULT NULL,
 ttl INT DEFAULT NULL,
 prio INT DEFAULT NULL,
 change_date INT DEFAULT NULL,
 disabled TINYINT(1) DEFAULT 0,
 ordername VARCHAR(255) BINARY DEFAULT NULL,
 auth TINYINT(1) DEFAULT 1,
 PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX nametype_index ON records(name,type);
CREATE INDEX domain_id ON records(domain_id);
CREATE INDEX ordername ON records (ordername);


CREATE TABLE supermasters (
 ip VARCHAR(64) NOT NULL,
 nameserver VARCHAR(255) NOT NULL,
 account VARCHAR(40) CHARACTER SET 'utf8' NOT NULL,
 PRIMARY KEY (ip, nameserver)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE TABLE comments (
 id INT AUTO_INCREMENT,
 domain_id INT NOT NULL,
 name VARCHAR(255) NOT NULL,
 type VARCHAR(10) NOT NULL,
 modified_at INT NOT NULL,
 account VARCHAR(40) CHARACTER SET 'utf8' DEFAULT NULL,
 comment TEXT CHARACTER SET 'utf8' NOT NULL,
 PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX comments_name_type_idx ON comments (name, type);
CREATE INDEX comments_order_idx ON comments (domain_id, modified_at);


CREATE TABLE domainmetadata (
 id INT AUTO_INCREMENT,
 domain_id INT NOT NULL,
 kind VARCHAR(32),
 content TEXT,
 PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX domainmetadata_idx ON domainmetadata (domain_id, kind);


CREATE TABLE cryptokeys (
 id INT AUTO_INCREMENT,
 domain_id INT NOT NULL,
 flags INT NOT NULL,
 active BOOL,
 content TEXT,
 PRIMARY KEY(id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX domainidindex ON cryptokeys(domain_id);


CREATE TABLE tsigkeys (
 id INT AUTO_INCREMENT,
 name VARCHAR(255),
 algorithm VARCHAR(50),
 secret VARCHAR(255),
 PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE UNIQUE INDEX namealgoindex ON tsigkeys(name, algorithm);

$ sudo systemctl disable systemd-resolved
$ sudo systemctl stop systemd-resolved

$ ls -lh /etc/resolv.conf
lrwxrwxrwx 1 root root 39 Jul 24 15:50 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf
$ sudo unlink /etc/resolv.conf

$ echo "nameserver 8.8.8.8" | sudo tee /etc/resolv.conf

新增 Ubuntu 22.04|20.04|18.04 的 PowerDNS 官方套件庫。

DNS on Ricky

Articles

Linux 系统误将 chmod 权限改成 了 000，如何恢复?

Laptops all have built-in security tokens these days

macOS

Mosdns-X

安裝

設定

systemd

在瀏覽器輸入網址並送出後，到底發生了什麼事？

在 Ubuntu 22.04|20.04|18.04 安裝 PowerDNS 與 PowerDNS-Admin

安裝 PowerDNS

Linux 系统误将 chmod 权限改成了 000，如何恢复?