FRITZ!Box修改DNS路由后WireGuard VPN无法连接的故障排查求助

大家好，我最近在给家里网络配置Pi-Hole拦截设备硬编码DNS后，遇到了WireGuard VPN彻底无法连接的问题，想请各位帮忙分析原因、提供排查思路。以下是我的完整情况说明：

网络基础环境 #

• 路由器：FRITZ!Box 6591 Cable
• Pi-Hole设备：树莓派Zero W，通过LAN连接路由器，IP地址为192.168.178.61
• 原本Pi-Hole与整个网络运行正常，问题出现在我修改DNS路由规则之后

前期操作（拦截硬编码DNS） #

我发现家里不少设备（如谷歌系设备）会绕过路由器指定的DNS，使用硬编码的8.8.8.8/8.8.4.4，于是通过FRITZ!Box配置路由规则拦截：

• 添加两条IPv4静态路由：将目标地址8.8.8.8和8.8.4.4（子网掩码均设为255.255.255.255），全部转发至Pi-Hole的IP 192.168.178.61
• 初始验证有效：ping这两个谷歌DNS地址均超时，符合拦截预期

当前核心问题 #

配置完上述路由规则后，原本正常连接的WireGuard VPN突然中断，之后无论用哪台设备尝试，都无法重新建立连接。

WireGuard VPN客户端配置 #

[Interface]
PrivateKey = [REDACTED FOR PRIVACY]
Address = 192.168.178.202/24
DNS = 192.168.178.1, fritz.box

[Peer]
PublicKey = [REDACTED FOR PRIVACY]
PresharedKey = [REDACTED FOR PRIVACY]
AllowedIPs = 192.168.178.0/24, 0.0.0.0/0
Endpoint = REDACTEDFORPRIVACY.myfritz.net:50974
PersistentKeepalive = 25

VPN客户端关键日志片段 #

12:45:53 - peer(2MQH…8IT4) - UAPI: Updating endpoint
12:45:53 - Routine: receive incoming v4 - stopped
12:45:53 - Routine: receive incoming v6 - stopped
12:45:53 - UDP bind has been updated
12:45:53 - Routine: receive incoming v6 - started
12:45:53 - Routine: receive incoming v4 - started
12:45:58 - peer(2MQH…8IT4) - Handshake did not complete after 5 seconds, retrying (try 2)
12:45:58 - peer(2MQH…8IT4) - Sending handshake initiation
12:46:04 - peer(2MQH…8IT4) - Handshake did not complete after 5 seconds, retrying (try 2)
12:46:04 - peer(2MQH…8IT4) - Sending handshake initiation
12:46:09 - peer(2MQH…8IT4) - Handshake did not complete after 5 seconds, retrying (try 2)
12:46:09 - peer(2MQH…8IT4) - Sending handshake initiation

补充说明 #

家里的外网连接本身正常——我仍能通过远程服务控制智能家居设备，说明路由器的外网出口没有问题。

备注：内容来源于stack exchange，提问作者FledDev