从上个月开始，我的 Ubuntu 18.04 开始随机掉线，我换了网线，现在也没用了。不知道这种情况会持续多久，可能几天或几小时。
这是日志：
Sep 9 12:09:56 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568002196.7542] connectivity: (eno1) timed out
Sep 9 12:09:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via systemd: servicename='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:09:56 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:09:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:09:56 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:09:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Sep 9 12:09:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Sep 9 12:14:27 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568002467.7598] connectivity: (eno1) response shorter than expected 'NetworkManager is online '; assuming captive portal.
Sep 9 12:14:27 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:14:27 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:14:27 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:14:27 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:14:27 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Sep 9 12:14:27 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Sep 9 12:14:28 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568002468.1303] connectivity: (wlx74da38f4306d) response did not match expected response 'Net workManager is online'; assuming captive portal.
Sep 9 12:16:56 C249-SYS-7048GR-TR dhclient[26148]: message repeated 5 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0) ]
Sep 9 12:17:01 C249-SYS-7048GR-TR CRON[2668]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Sep 9 12:17:10 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)
Sep 9 12:19:27 C249-SYS-7048GR-TR dhclient[26148]: message repeated 10 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)]
Sep 9 12:19:27 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568002767.7711] connectivity: (wlx74da38f4306d) response did not match expected response 'Net workManager is online'; assuming captive portal.
Sep 9 12:19:45 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)
Sep 9 12:19:53 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)
Sep 9 12:19:56 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568002796.7539] connectivity: (eno1) timed out
Sep 9 12:19:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:19:56 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:19:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:19:56 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:19:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Sep 9 12:19:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Sep 9 12:20:01 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)
Sep 9 12:24:25 C249-SYS-7048GR-TR dhclient[26148]: message repeated 20 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0 )]
Sep 9 12:24:27 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003067.7583] connectivity: (eno1) response shorter than expected 'NetworkManager is online '; assuming captive portal.
Sep 9 12:24:27 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:24:27 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:24:27 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:24:27 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:24:27 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Sep 9 12:24:27 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Sep 9 12:24:28 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003068.0648] connectivity: (wlx74da38f4306d) response did not match expected response 'Net workManager is online'; assuming captive portal.
Sep 9 12:24:39 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0)
Sep 9 12:26:28 C249-SYS-7048GR-TR dhclient[26148]: message repeated 9 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 166.111.152.1 port 67 (xid=0x636e1ec0) ]
Sep 9 12:26:46 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)
Sep 9 12:29:17 C249-SYS-7048GR-TR dhclient[26148]: message repeated 11 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)]
Sep 9 12:29:27 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003367.7934] connectivity: (wlx74da38f4306d) response did not match expected response 'Net workManager is online'; assuming captive portal.
Sep 9 12:29:28 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)
Sep 9 12:29:39 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)
Sep 9 12:29:56 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003396.7560] connectivity: (eno1) timed out
Sep 9 12:29:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:29:56 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:29:56 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:29:56 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:29:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Sep 9 12:29:56 C249-SYS-7048GR-TR nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Sep 9 12:29:56 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)
Sep 9 12:31:25 C249-SYS-7048GR-TR dhclient[26148]: message repeated 6 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec 0)]
Sep 9 12:31:31 C249-SYS-7048GR-TR dhclient[22238]: PRC: Renewing lease on eno1.
Sep 9 12:31:31 C249-SYS-7048GR-TR dhclient[22238]: XMT: Renew on eno1, interval 9540ms.
Sep 9 12:31:31 C249-SYS-7048GR-TR dhclient[22238]: RCV: Reply message on eno1 from fe80::3e61:4ff:fe44:e9f6.
Sep 9 12:31:31 C249-SYS-7048GR-TR dhclient[22238]: IA_NA status code Success.
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8744] dhcp6 (eno1): valid_lft 7500
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8745] dhcp6 (eno1): preferred_lft 7200
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8745] dhcp6 (eno1): address 2402:f000:4:33:808::bb2
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8745] dhcp6 (eno1): nameserver '2402:f000:1:801::8:28'
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8745] dhcp6 (eno1): nameserver '2402:f000:1:801::8:29'
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8746] dhcp (eno1): domain search 'tsinghua.edu.cn.'
Sep 9 12:31:31 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003491.8746] dhcp6 (eno1): state changed bound -> bound, event ID="6b:81:63:7c|1568003491"Sep 9 12:31:31 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via sy stemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:31:31 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script Dispatcher Service...
Sep 9 12:31:31 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:31:31 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Dispatcher Service.
Sep 9 12:31:31 C249-SYS-7048GR-TR nm-dispatcher: req:1 'dhcp6-change' [eno1]: new request (1 scripts)
Sep 9 12:31:31 C249-SYS-7048GR-TR nm-dispatcher: req:1 'dhcp6-change' [eno1]: start running ordered scripts...
Sep 9 12:31:46 C249-SYS-7048GR-TR dhclient[26148]: DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec0)
Sep 9 12:33:07 C249-SYS-7048GR-TR kernel: [5772257.104657] RTW: rtl8822b_c2h_handler_no_io: C2H, ID=12 seq=32 len=32
Sep 9 12:34:10 C249-SYS-7048GR-TR dhclient[26148]: message repeated 9 times: [ DHCPREQUEST of 166.111.154.239 on eno1 to 255.255.255.255 port 67 (xid=0x636e1ec 0)]
Sep 9 12:34:15 C249-SYS-7048GR-TR avahi-daemon[1273]: Withdrawing address record for 166.111.154.239 on eno1.
Sep 9 12:34:15 C249-SYS-7048GR-TR avahi-daemon[1273]: Leaving mDNS multicast group on interface eno1.IPv4 with address 166.111.154.239.
Sep 9 12:34:15 C249-SYS-7048GR-TR avahi-daemon[1273]: Interface eno1.IPv4 no longer relevant for mDNS.
Sep 9 12:34:15 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003655.9355] policy: set 'Tsinghua-IPv4 1' (wlx74da38f4306d) as default for IPv4 routing a nd DNS
Sep 9 12:34:15 C249-SYS-7048GR-TR gsd-sharing[2444]: Failed to StopUnit service: GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit rygel.service not loaded .
Sep 9 12:34:15 C249-SYS-7048GR-TR gsd-sharing[2444]: Failed to StopUnit service: GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit gnome-remote-desktop.ser vice not loaded.
Sep 9 12:34:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003656.1671] dhcp4 (eno1): state changed bound -> expire
Sep 9 12:34:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003656.1995] dhcp4 (eno1): canceled DHCP transaction, DHCP client pid 26148
Sep 9 12:34:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003656.1996] dhcp4 (eno1): state changed expire -> done
Sep 9 12:34:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003656.1999] device (eno1): scheduling DHCPv4 restart in 120 seconds, 3 tries left (reason : lease expired)
Sep 9 12:34:17 C249-SYS-7048GR-TR kernel: [5772327.257157] RTW: rtl8822b_c2h_handler_no_io: C2H, ID=12 seq=33 len=32
Sep 9 12:34:17 C249-SYS-7048GR-TR kernel: [5772327.568424] RTW: traffic_status_watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:22,rx_unicast:11)
Sep 9 12:34:21 C249-SYS-7048GR-TR kernel: [5772331.600444] RTW: traffic_status_watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:13,rx_unicast:8)
Sep 9 12:34:27 C249-SYS-7048GR-TR kernel: [5772337.648454] RTW: traffic_status_watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:14,rx_unicast:9)
Sep 9 12:34:27 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003667.7673] connectivity: (wlx74da38f4306d) response did not match expected response 'Net workManager is online'; assuming captive portal.
Sep 9 12:34:51 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StScrollBar' tried to allocate a size of -13.00 x 14.00
Sep 9 12:34:51 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StBoxLayout' tried to allocate a size of -13.00 x 1.00
Sep 9 12:34:51 C249-SYS-7048GR-TR kernel: [5772361.840591] RTW: traffic_status_ watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:11,rx_unicast:8)
Sep 9 12:34:53 C249-SYS-7048GR-TR kernel: [5772363.856573] RTW: traffic_status_ watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:11,rx_unicast:7)
Sep 9 12:34:56 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003696.756 1] connectivity: (eno1) timed out
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[1]: Stopping User Manager for UID 100 3...
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped target Default.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped target Basic System.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped target Paths.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped Pending report trigge r for Ubuntu Report.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped target Timers.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Stopped target Sockets.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed GnuPG cryptographic ag ent and passphrase cache (restricted).
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed GnuPG network certific ate management daemon.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed GnuPG cryptographic ag ent and passphrase cache (access for web browsers).
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed GnuPG cryptographic ag ent and passphrase cache.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed GnuPG cryptographic ag ent (ssh-agent emulation).
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Closed D-Bus User Message Bus Socket.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Reached target Shutdown.
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Starting Exit the Session...
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[27245]: Received SIGRTMIN+24 from PID 5995 (kill).
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[1]: Stopped User Manager for UID 1003 .
Sep 9 12:35:58 C249-SYS-7048GR-TR systemd[1]: Removed slice User Slice of jsbyy sheng.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[1]: Stopping User Manager for UID 100 7...
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped target Default.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped target Basic System.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped target Paths.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped Pending report trigge r for Ubuntu Report.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped target Sockets.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed GnuPG network certific ate management daemon.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed GnuPG cryptographic ag ent and passphrase cache.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed D-Bus User Message Bus Socket.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed GnuPG cryptographic ag ent and passphrase cache (access for web browsers).
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Stopped target Timers.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed GnuPG cryptographic ag ent (ssh-agent emulation).
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Closed GnuPG cryptographic ag ent and passphrase cache (restricted).
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Reached target Shutdown.
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Starting Exit the Session...
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[27098]: Received SIGRTMIN+24 from PID 5998 (kill).
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[1]: Stopped User Manager for UID 1007 .
Sep 9 12:35:59 C249-SYS-7048GR-TR systemd[1]: Removed slice User Slice of klyjm .
Sep 9 12:35:59 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StScrollBar' tried to allocate a size of -13.00 x 14.00
Sep 9 12:35:59 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StBoxLayout' tried to allocate a size of -13.00 x 1.00
Sep 9 12:36:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003776.758 6] dhcp4 (eno1): activation: beginning transaction (timeout in 45 seconds)
Sep 9 12:36:16 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003776.761 7] dhcp4 (eno1): dhclient started with pid 6000
Sep 9 12:36:16 C249-SYS-7048GR-TR dhclient[6000]: DHCPDISCOVER on eno1 to 255.2 55.255.255 port 67 interval 3 (xid=0xf1c95c04)
Sep 9 12:36:17 C249-SYS-7048GR-TR dhclient[6000]: DHCPREQUEST of 166.111.154.23 9 on eno1 to 255.255.255.255 port 67 (xid=0x45cc9f1)
Sep 9 12:36:17 C249-SYS-7048GR-TR dhclient[6000]: DHCPOFFER of 166.111.154.239 from 166.111.152.1
Sep 9 12:36:17 C249-SYS-7048GR-TR dhclient[6000]: DHCPACK of 166.111.154.239 fr om 166.111.152.1
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.873 9] dhcp4 (eno1): address 166.111.154.239
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.873 9] dhcp4 (eno1): plen 22 (255.255.252.0)
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.873 9] dhcp4 (eno1): gateway 166.111.152.1
Sep 9 12:36:17 C249-SYS-7048GR-TR avahi-daemon[1273]: Joining mDNS multicast gr oup on interface eno1.IPv4 with address 166.111.154.239.
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.874 0] dhcp4 (eno1): lease time 3600
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.874 0] dhcp4 (eno1): nameserver '166.111.8.28'
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.874 0] dhcp4 (eno1): nameserver '166.111.8.29'
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.874 0] dhcp4 (eno1): domain name 'tsinghua.edu.cn'
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.874 0] dhcp4 (eno1): state changed unknown -> bound
Sep 9 12:36:17 C249-SYS-7048GR-TR avahi-daemon[1273]: New relevant interface en o1.IPv4 for mDNS.
Sep 9 12:36:17 C249-SYS-7048GR-TR avahi-daemon[1273]: Registering new address r ecord for 166.111.154.239 on eno1.IPv4.
Sep 9 12:36:17 C249-SYS-7048GR-TR NetworkManager[1248]: <info> [1568003777.876 8] policy: set 'Wired connection 1' (eno1) as default for IPv4 routing and DNS
Sep 9 12:36:17 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Activating via sy stemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.n m-dispatcher.service' requested by ':1.8' (uid=0 pid=1248 comm="/usr/sbin/Networ kManager --no-daemon " label="unconfined")
Sep 9 12:36:17 C249-SYS-7048GR-TR systemd[1]: Starting Network Manager Script D ispatcher Service...
Sep 9 12:36:17 C249-SYS-7048GR-TR gsd-sharing[2444]: Failed to StopUnit service : GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit rygel.service not loaded .
Sep 9 12:36:17 C249-SYS-7048GR-TR dhclient[6000]: bound to 166.111.154.239 -- r enewal in 1464 seconds.
Sep 9 12:36:17 C249-SYS-7048GR-TR gsd-sharing[2444]: Failed to StopUnit service : GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit gnome-remote-desktop.ser vice not loaded.
Sep 9 12:36:17 C249-SYS-7048GR-TR dbus-daemon[1243]: [system] Successfully acti vated service 'org.freedesktop.nm_dispatcher'
Sep 9 12:36:17 C249-SYS-7048GR-TR systemd[1]: Started Network Manager Script Di spatcher Service.
Sep 9 12:36:17 C249-SYS-7048GR-TR nm-dispatcher: req:1 'dhcp4-change' [eno1]: n ew request (1 scripts)
Sep 9 12:36:17 C249-SYS-7048GR-TR nm-dispatcher: req:1 'dhcp4-change' [eno1]: s tart running ordered scripts...
Sep 9 12:36:18 C249-SYS-7048GR-TR kernel: [5772448.528996] RTW: traffic_status_ watchdog(wlx74da38f4306d) acqiure wake_lock for 4500 ms(tx:13,rx_unicast:9)
Sep 9 12:36:55 C249-SYS-7048GR-TR colord[1353]: failed to get session [pid 9928 ]: No data available
Sep 9 12:37:02 C249-SYS-7048GR-TR colord[1353]: failed to get session [pid 9928 ]: No data available
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[1]: Created slice User Slice of klyjm .
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[1]: Starting User Manager for UID 100 7...
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[1]: Started Session 3342 of user klyj m.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on GnuPG cryptograph ic agent and passphrase cache (restricted).
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on GnuPG network cer tificate management daemon.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Starting D-Bus User Message Bu s Socket.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on GnuPG cryptograph ic agent and passphrase cache (access for web browsers).
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Started Pending report trigger for Ubuntu Report.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Reached target Paths.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on GnuPG cryptograph ic agent (ssh-agent emulation).
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on GnuPG cryptograph ic agent and passphrase cache.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Reached target Timers.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Listening on D-Bus User Messag e Bus Socket.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Reached target Sockets.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Reached target Basic System.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Reached target Default.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[6043]: Startup finished in 55ms.
Sep 9 12:37:03 C249-SYS-7048GR-TR systemd[1]: Started User Manager for UID 1007 .
Sep 9 12:37:04 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StScrollBar' tried to allocate a size of -13.00 x 14.00
Sep 9 12:37:04 C249-SYS-7048GR-TR gnome-shell[1697]: clutter-actor.c:10063: Act or 'StBoxLayout' tried to allocate a size of -13.00 x 1.00
这是 lshw：
*-network:0
description: Ethernet interface
product: I350 Gigabit Network Connection
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:81:00.0
logical name: eno1
version: 01
serial: ac:1f:6b:81:63:7c
size: 1Gbit/s
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: pm msi msix pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.4.0-k duplex=full firmware=1.63, 0x800009fa ip=166.111.154.239 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
resources: irq:31 memory:fb020000-fb03ffff ioport:f020(size=32) memory:fb044000-fb047fff memory:384000000000-38400001ffff memory:384000020000-38400003ffff
*-network:1
description: Ethernet interface
product: I350 Gigabit Network Connection
vendor: Intel Corporation
physical id: 0.1
bus info: pci@0000:81:00.1
logical name: eno2
version: 01
serial: ac:1f:6b:81:63:7d
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: pm msi msix pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.4.0-k firmware=1.63, 0x800009fa latency=0 link=no multicast=yes port=twisted pair
resources: irq:47 memory:fb000000-fb01ffff ioport:f000(size=32) memory:fb040000-fb043fff memory:384000040000-38400005ffff memory:384000060000-38400007ffff
*-network
description: Wireless interface
physical id: 3
bus info: usb@3:2
logical name: wlx74da38f4306d
serial: 74:da:38:f4:30:6d
capabilities: ethernet physical wireless
configuration: broadcast=yes driver=rtl8822bu ip=183.173.88.156 multicast=yes wireless=IEEE 802.11AC
这是答案：
nameserver 127.0.0.53
options edns0
search tsinghua.edu.cn
答案1
根据我所看到的信息，您提供的信息表明问题出在您的上游连接被中断。在这种情况下，是由中国北京清华大学的网络基础设施中的某些因素造成的。
当然，NIC 电缆、网络硬件或数据柜中的某些东西可能是罪魁祸首。但我没有发现任何证据表明 Ubuntu 导致了此故障。