各位大佬好，我折腾好几天了还是没解决这个问题，想请大家支支招！

我的环境与配置情况： #

• 硬件：树莓派通过两个TP-Link TL-PA4010电力线适配器连接海康摄像头
• 系统：树莓派跑的是标准Raspbian（Debian GNU/Linux 11 (bullseye)）
• 树莓派eth0静态IP配置（/etc/dhcpcd.conf）：

interface eth0
static ip_address=192.168.0.10/24

• 用dnsmasq搭建的DHCP服务器，配置文件内容：

# Disable DNS
port=0

# Configuring the DHCP server
interface=eth0
dhcp-leasefile=/var/lib/misc/dnsmasq.leases

# The MAC address of the IP camera
dhcp-host=xx:xx:xx:xx:xx:xx,192.168.0.11

# I've added this later, didn't do anything
dhcp-authoritative

# Some logging
log-dhcp
log-queries
log-facility=/var/log/dnsmasq.log

问题现象： #

这个配置之前是能用的，我能正常获取摄像头的图像，但现在摄像头死活连不上树莓派的DHCP服务器——拿不到IP地址。

• 摄像头连我家主网的话，能正常获取IP，也能打开它的网页管理界面
• 我已经把摄像头重置到出厂设置，重新设为DHCP模式，还是没用
• 用tcpdump抓eth0的流量，能看到摄像头一直在发DHCP请求：

17:46:36.725552 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from xx:xx:xx:xx:xx:xx (oui Unknown), length 284
17:46:39.726180 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from xx:xx:xx:xx:xx:xx (oui Unknown), length 284
17:46:42.727918 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from xx:xx:xx:xx:xx:xx (oui Unknown), length 284

• 但dnsmasq完全没响应，日志里只有启动记录，没有任何DHCP相关的处理日志：

Apr 29 17:33:57 dnsmasq[590]: started, version 2.85 DNS disabled
Apr 29 17:33:57 dnsmasq[590]: compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile

已尝试的操作： #

• 重置摄像头到出厂设置，重新配置为DHCP模式
• 删除了旧的lease文件/var/lib/dhcp/dhclient.leases（之前成功连接的记录在里面，看网上说删了试试，但没用）
• 确认dnsmasq服务运行正常，systemd状态如下：

● dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
Loaded: loaded (/lib/systemd/system/dnsmasq.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2023-04-29 17:33:57 CEST; 15min ago
Process: 538 ExecStartPre=/etc/init.d/dnsmasq checkconfig (code=exited, status=0/SUCCESS)
Process: 570 ExecStart=/etc/init.d/dnsmasq systemd-exec (code=exited, status=0/SUCCESS)
Process: 594 ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf (code=exited, status=0/SUCCESS)
Main PID: 590 (dnsmasq)
Tasks: 1 (limit: 779)
CPU: 435ms
CGroup: /system.slice/dnsmasq.service
└─590 /usr/sbin/dnsmasq -x /run/dnsmasq/dnsmasq.pid -u dnsmasq -r /run/dnsmasq/resolv.conf -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service --trust-anchor=.,20326,8,2,e06d44b80b8f1d3>

Apr 29 17:33:55 raspberrypi systemd[1]: Starting dnsmasq - A lightweight DHCP and caching DNS server...
Apr 29 17:33:57 raspberrypi systemd[1]: Started dnsmasq - A lightweight DHCP and caching DNS server.

• 确认树莓派没有防火墙，执行sudo systemctl stop firewall提示服务未加载，说明没装防火墙

我的猜测： #

我觉得问题应该出在树莓派这边，因为：

• 能抓到摄像头的流量，说明电力线适配器是正常工作的
• 摄像头能从家里网关的DHCP服务器拿到IP，说明摄像头本身没问题

现在实在没头绪了，想问问大家可能是什么问题？还有哪些可以排查的方向？

备注：内容来源于stack exchange，提问作者Luke Skywalker