问题现象 #

我手上一台Windows 11设备出现了烦人的网络故障：每天会多次发生有线网络断开的情况，每次断网时长大概5秒左右，频率毫无规律——有时候几分钟内断好几次，有时候间隔15分钟左右才断一次。每次断网时，系统事件日志都会记录Event 27：「Network link is disconnected」（网络链路已断开）。

值得注意的是，同一网络下的其他所有设备都正常联网，只有这台Windows 11设备出现问题。

初步怀疑方向 #

我最初猜测问题出在DHCP续约流程上，因为负责网络DHCP的Nokia 10G PON ONT（光猫）每次断网时都会生成相关日志（故障设备的主机名为aquanaut）。

DHCP服务器日志详情 #

光猫记录的相关日志如下：

[notice] <133>1 2023-12-25T21:29:03.489941+00:00 AONT dhcpd 3064 - -  DHCP-Comm:[check_port_ingress] iftype= ifname=eth4.0
[notice] <133>1 2023-12-25T21:29:03.489969+00:00 AONT dhcpd 3064 - -  Try to read file /configs/etc/dhcpsnoop.conf_orig contents and look for interface eth4.0!
[notice] <133>1 2023-12-25T21:29:03.490011+00:00 AONT dhcpd 3064 - -  read_gre_config: Read file /configs/etc/dhcpsnoop.conf_orig with data
[notice] <133>1 2023-12-25T21:29:03.490027+00:00 AONT dhcpd 3064 - -  option_82=1
[notice] <133>1 2023-12-25T21:29:03.490043+00:00 AONT dhcpd 3064 - -  option_60=1
[notice] <133>1 2023-12-25T21:29:03.490058+00:00 AONT dhcpd 3064 - -  service_id=
[notice] <133>1 2023-12-25T21:29:03.490073+00:00 AONT dhcpd 3064 - -  cktid_format=1
[notice] <133>1 2023-12-25T21:29:03.490087+00:00 AONT dhcpd 3064 - -  rmtid_format=1
[notice] <133>1 2023-12-25T21:29:03.490109+00:00 AONT dhcpd 3064 - -  Contents of file /configs/etc/dhcpsnoop.conf_orig
[notice] <133>1 2023-12-25T21:29:03.490124+00:00 AONT dhcpd 3064 - -  option_82=1
[notice] <133>1 2023-12-25T21:29:03.490139+00:00 AONT dhcpd 3064 - -  option_60=1
[notice] <133>1 2023-12-25T21:29:03.503694+00:00 AONT dhcpd 3064 - -  service_id=
[notice] <133>1 2023-12-25T21:29:03.503722+00:00 AONT dhcpd 3064 - -  cktid_format=1
[notice] <133>1 2023-12-25T21:29:03.503738+00:00 AONT dhcpd 3064 - -  rmtid_format=1
[notice] <133>1 2023-12-25T21:29:03.504463+00:00 AONT dhcpd 3064 - -  DHCP-Comm:sendACK() the Host-Name:aquanautQ#013 length:[8].
[notice] <133>1 2023-12-25T21:29:03.504492+00:00 AONT dhcpd 3064 - -  DHCP-Comm:create_or_update_lease() MAC:ADDRESS:REDACTED ip(8101a8c0),portid=0, addrServPool default, lease=86400.
[notice] <133>1 2023-12-25T21:29:33.613828+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:29:35.655079+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:32:03.728847+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:32:05.775116+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:34:33.843828+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:34:35.890088+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:34:45.063829+00:00 AONT dhcpc 4329 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:34:47.105269+00:00 AONT dhcpc 4329 - -  dhcpc:mask=100000,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:37:03.958833+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:37:06.005104+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:39:34.068833+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:39:36.110075+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:42:04.183835+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:42:06.235023+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:44:34.298833+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:44:36.340118+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:47:04.413838+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:47:06.465075+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:49:34.523829+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:49:36.575100+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:52:04.638830+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:52:06.685968+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:54:34.748836+00:00 AONT dhcpc 4317 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:54:36.795056+00:00 AONT dhcpc 4317 - -  dhcpc:mask=0,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,
[notice] <133>1 2023-12-25T21:54:45.178837+00:00 AONT dhcpc 4329 - -  DHCP-Comm:send_renew() Unicasts a DHCP renew message
[notice] <133>1 2023-12-25T21:54:47.234959+00:00 AONT dhcpc 4329 - -  dhcpc:mask=100000,ip=0.0.0.0,mask=0.0.0.0,tftpserver=0.0.0.0,

已尝试的排查措施 #

为了定位问题，我试过了各种常见的排查手段，但都没有效果：

• 更换了3种不同类型的网卡：包括板载网卡、PCIE独立网卡、USB外接网卡，而且这些网卡的芯片组来自不同厂商
• 禁用了所有第三方软件，甚至彻底重装了Windows系统
• 移除了网络中的其他所有设备，更换了外部网线

最终解决方案 #

折腾了半天后才发现，问题根源是机箱内部的以太网延长线故障——因为机箱的特殊结构，网卡没有直接暴露在机箱背面，而是通过一根小型延长线连接到后置接口，这根内部延长线出现了接触不良或者损坏的情况。

之前关注的DHCP日志其实只是断网带来的症状，并不是导致断网的原因，属于典型的“误判方向”。

备注：内容来源于stack exchange，提问作者Jordan Morris