大约一个月前，我在父母家打开笔记本电脑，发现 wifi 停止工作。我的路由器连接总是有问题，但我的电脑从未完全停止连接互联网。
在过去的一个月里我尝试过：
iwlwifi从 iso重新安装- 将 Ubuntu 从 18.04 升级到 20.04
- 处理了这么多文件，寻找类似问题的答案。我做了很多次，记不清自己做了什么。
有一次，在我按照这个答案操作后，我的wifi连接恢复了： 未找到 Wi-Fi 适配器 - Ubuntu - iwlwifi。但当我第二次去看望父母的时候，wifi又断了，就这样。
我相信它与 DNS 有关，因为我可以ping 8.8.8.8但不能ping google.com。
我想重新开始
编辑：
输出sudo journalctl -b 0 -u NetworkManager：
-- Logs begin at Sun 2021-08-01 23:19:38 IDT, end at Wed 2021-10-06 13:23:15 IDT. --
Oct 06 13:22:32 leah-Vostro-5481 systemd[1]: Starting Network Manager...
Oct 06 13:22:32 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515752.8859] NetworkManager (version 1.22.10) is starting... (for the first time)
Oct 06 13:22:32 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515752.8861] Read config: /etc/NetworkManager/NetworkManager.conf (lib: 10-dns-resolved.conf, 20-connectivity-ubuntu.conf, no-mac-addr-change.conf) (run: 10-globally-managed-devices.conf) (etc: default-wifi-powersave-on.conf)
Oct 06 13:22:32 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515752.8981] bus-manager: acquired D-Bus service "org.freedesktop.NetworkManager"
Oct 06 13:22:32 leah-Vostro-5481 systemd[1]: Started Network Manager.
Oct 06 13:22:32 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515752.9063] manager[0x564b4305e030]: monitoring kernel firmware directory '/lib/firmware'.
Oct 06 13:22:32 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515752.9068] monitoring ifupdown state file '/run/network/ifstate'.
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2153] hostname: hostname: using hostnamed
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2153] hostname: hostname changed from (none) to "leah-Vostro-5481"
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2157] dns-mgr[0x564b43045290]: init: dns=systemd-resolved rc-manager=symlink, plugin=systemd-resolved
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2169] rfkill0: found Wi-Fi radio killswitch (at /sys/devices/pci0000:00/0000:00:14.3/ieee80211/phy0/rfkill0) (driver iwlwifi)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2191] manager[0x564b4305e030]: rfkill: Wi-Fi hardware radio set enabled
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2192] manager[0x564b4305e030]: rfkill: WWAN hardware radio set enabled
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2295] Loaded device plugin: NMTeamFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-device-plugin-team.so)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2306] Loaded device plugin: NMAtmManager (/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-device-plugin-adsl.so)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2340] Loaded device plugin: NMBluezManager (/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-device-plugin-bluetooth.so)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2359] Loaded device plugin: NMWwanFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-device-plugin-wwan.so)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2370] Loaded device plugin: NMWifiFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-device-plugin-wifi.so)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2375] manager: rfkill: Wi-Fi enabled by radio killswitch; enabled by state file
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2376] manager: rfkill: WWAN enabled by radio killswitch; enabled by state file
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2378] manager: Networking is enabled by state file
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2379] dhcp-init: Using DHCP client 'internal'
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2393] settings: Loaded settings plugin: ifupdown ("/usr/lib/x86_64-linux-gnu/NetworkManager/1.22.10/libnm-settings-plugin-ifupdown.so")
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2394] settings: Loaded settings plugin: keyfile (internal)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2394] ifupdown: management mode: unmanaged
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2396] ifupdown: interface-parser: parsing file /etc/network/interfaces
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.2398] ifupdown: interface-parser: finished parsing file /etc/network/interfaces
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.3439] device (lo): carrier: link connected
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.3482] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/1)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.3540] manager: (enp3s0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.3624] device (enp3s0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.4938] device (wlo1): driver supports Access Point (AP) mode
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.4945] manager: (wlo1): new 802.11 Wi-Fi device (/org/freedesktop/NetworkManager/Devices/3)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.4959] device (wlo1): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <warn> [1633515753.6787] Error: failed to open /run/network/ifstate
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.6905] modem-manager: ModemManager available
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7037] manager: (50:8F:4C:27:88:35): new Bluetooth device (/org/freedesktop/NetworkManager/Devices/4)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7059] device (50:8F:4C:27:88:35): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7230] supplicant: wpa_supplicant running
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7231] device (wlo1): supplicant interface state: init -> starting
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7237] device (50:8F:4C:27:88:35): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7943] sup-iface[0x564b4306c920,wlo1]: supports 5 scan SSIDs
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7951] device (wlo1): supplicant interface state: starting -> ready
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7952] Wi-Fi P2P device controlled by interface wlo1 created
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7956] manager: (p2p-dev-wlo1): new 802.11 Wi-Fi P2P device (/org/freedesktop/NetworkManager/Devices/5)
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7960] device (p2p-dev-wlo1): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7972] device (p2p-dev-wlo1): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515753.7976] device (wlo1): state change: unavailable -> disconnected (reason 'supplicant-available', sys-iface-state: 'managed')
Oct 06 13:22:33 leah-Vostro-5481 NetworkManager[1192]: <warn> [1633515753.8021] sup-iface: failed to cancel p2p connect: P2P cancel failed
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2041] policy: auto-activating connection 'TP-Link_2278' (6e7be3e3-c700-4be8-b974-f4495a743efd)
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2046] device (wlo1): Activation: starting connection 'TP-Link_2278' (6e7be3e3-c700-4be8-b974-f4495a743efd)
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2047] device (wlo1): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2050] manager: NetworkManager state is now CONNECTING
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2053] device (wlo1): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2055] device (wlo1): Activation: (wifi) access point 'TP-Link_2278' has security, but secrets are required.
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2056] device (wlo1): state change: config -> need-auth (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2057] sup-iface[0x564b4306c920,wlo1]: wps: type pbc start...
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2081] device (wlo1): state change: need-auth -> prepare (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2084] device (wlo1): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2086] device (wlo1): Activation: (wifi) connection 'TP-Link_2278' has security, and secrets exist. No new secrets needed.
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2086] Config: added 'ssid' value 'TP-Link_2278'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2086] Config: added 'scan_ssid' value '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2086] Config: added 'bgscan' value 'simple:30:-70:86400'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2087] Config: added 'key_mgmt' value 'WPA-PSK WPA-PSK-SHA256 FT-PSK'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2087] Config: added 'psk' value '<hidden>'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2186] device (wlo1): supplicant interface state: ready -> authenticating
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2186] device (p2p-dev-wlo1): supplicant management interface state: ready -> authenticating
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2410] device (wlo1): supplicant interface state: authenticating -> associating
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2410] device (p2p-dev-wlo1): supplicant management interface state: authenticating -> associating
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2623] device (wlo1): supplicant interface state: associating -> associated
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.2624] device (p2p-dev-wlo1): supplicant management interface state: associating -> associated
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3579] device (wlo1): supplicant interface state: associated -> 4-way handshake
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3579] device (p2p-dev-wlo1): supplicant management interface state: associated -> 4-way handshake
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3734] device (wlo1): supplicant interface state: 4-way handshake -> completed
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3734] device (wlo1): Activation: (wifi) Stage 2 of 5 (Device Configure) successful. Connected to wireless network "TP-Link_2278"
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3734] device (p2p-dev-wlo1): supplicant management interface state: 4-way handshake -> completed
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3735] device (wlo1): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3739] dhcp4 (wlo1): activation: beginning transaction (timeout in 45 seconds)
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option dhcp_lease_time => '7200'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option domain_name_servers => '192.168.0.1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option expiry => '1633522957'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option ip_address => '192.168.0.107'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_broadcast_address => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_domain_name => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_domain_name_servers => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_domain_search => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_host_name => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3892] dhcp4 (wlo1): option requested_interface_mtu => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_ms_classless_static_routes => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_nis_domain => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_nis_servers => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_ntp_servers => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_rfc3442_classless_static_routes => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_root_path => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_routers => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_static_routes => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_subnet_mask => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_time_offset => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option requested_wpad => '1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option routers => '192.168.0.1'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): option subnet_mask => '255.255.255.0'
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3893] dhcp4 (wlo1): state changed unknown -> bound
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3907] device (wlo1): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3922] device (wlo1): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3924] device (wlo1): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3927] manager: NetworkManager state is now CONNECTED_LOCAL
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3937] manager: NetworkManager state is now CONNECTED_SITE
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3938] policy: set 'TP-Link_2278' (wlo1) as default for IPv4 routing and DNS
Oct 06 13:22:37 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515757.3942] device (wlo1): Activation: successful, device activated.
Oct 06 13:22:52 leah-Vostro-5481 NetworkManager[1192]: <info> [1633515772.1685] agent-manager: agent[179b3e28d31c4ae4,:1.73/org.gnome.Shell.NetworkAgent/1001]: agent registered
`iwconfig' 的输出：
lo no wireless extensions.
enp3s0 no wireless extensions.
wlo1 IEEE 802.11 ESSID:"TP-Link_2278"
Mode:Managed Frequency:2.417 GHz Access Point: 68:FF:7B:C8:22:78
Bit Rate=150 Mb/s Tx-Power=22 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:off
Link Quality=64/70 Signal level=-46 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:192 Missed beacon:0