Keuin's

简单可靠的IPv6 DDNS

应用场景：在拥有IPv6地址的机器上，运行一个守护进程，当本机IPv6地址变化时，主动更新DNS解析记录，即实现了DDNS。

代码

/etc/systemd/system/ddns.service

[Unit]
Description=Monitor IPv6 changes and update DDNS
Wants=network.target
After=network-online.target

[Service]
Type=simple
Restart=always
ExecStart=/bin/bash /usr/local/bin/update-ddns.sh
WorkingDirectory=/tmp
User=ddns
Group=ddns
Restart=on-failure

[Install]
WantedBy=multi-user.target

/usr/local/bin/update-ddns.sh

#!/bin/bash

IFACE=enp6s0 # 这里修改为你的IPv6网卡接口名称
last_addr=''

# check if the interface exists
if ! ip link show $IFACE > /dev/null 2>&1; then
    echo "Error: network interface $IFACE does not exist"
    exit 1
fi

update_ddns() {
        IP="$1"
        if [[ "$IP" == "" ]]; then
                echo 'no valid IPv6 address extracted from monitor, get from remote server'
                IP=`curl --proxy '' -s https://ipv6.ddnspod.com`
        fi
        echo "New IP Address: '${IP}'"
        # 在这里添加你的curl命令，更新AAAA记录的地址值为$IP
}

# 服务启动时立刻更新一次
update_ddns

# 只要以2开头的IPv6地址，过滤掉ULA和link-local地址
ip mon addr dev $IFACE | sed -nu -r "s/^2: $IFACE[[:space:]]+inet6 (2[0-9a-f:]+).+$/\\1/p" | while read this_addr; do
    if [[ "$last_addr" != "$this_addr" ]]; then
        echo "IPv6 address changed: '${this_addr}', previous one: '$last_addr'";
        last_addr="$this_addr"
        update_ddns "$this_addr"
    fi
done

优缺点

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