编辑/解决方法：禁用 IPv6 可以解决问题。
我的Forticlient VPN升级到 23.04 后就停止工作了。
症状是，在将我的用户和密码输入 Forticlient 后，它会连接，然后立即断开连接。
我卸载/重新安装，从 forticlient 6.4 升级到 7.0，但没有帮助。22.10 上的完全相同的配置有效。
查看日志失败尝试（23.04），看来 ifupdown 脚本可能有问题（？）：
mai 15 20:34:04 tibook NetworkManager[4875]: <info> [1684175644.9842] manager: (vpn001782c1f8): new Tun device (/org/freedesktop/NetworkManager/Devices/11)
mai 15 20:34:04 tibook NetworkManager[4875]: <info> [1684175644.9929] device (vpn001782c1f8): state change: unmanaged -> unavailable (reason 'connection-assumed', sys-iface-state: 'external')
mai 15 20:34:04 tibook NetworkManager[4875]: <info> [1684175644.9934] device (vpn001782c1f8): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external')
mai 15 20:34:04 tibook NetworkManager[4875]: <info> [1684175644.9940] device (vpn001782c1f8): Activation: starting connection 'vpn001782c1f8' (d337717e-af5e-4281-a525-c735bf2acf27)
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0014] device (vpn001782c1f8): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0016] device (vpn001782c1f8): state change: prepare -> config (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0017] device (vpn001782c1f8): state change: config -> ip-config (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0020] device (vpn001782c1f8): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook dbus-daemon[4249]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.20' (uid=0 pid=4875 comm="/usr/sbin/NetworkManager --no-daemon" label="unconfined")
mai 15 20:34:05 tibook systemd[1]: Starting NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service...
mai 15 20:34:05 tibook dbus-daemon[4249]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
mai 15 20:34:05 tibook systemd[1]: Started NetworkManager-dispatcher.service - Network Manager Script Dispatcher Service.
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0614] device (vpn001782c1f8): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0618] device (vpn001782c1f8): state change: secondaries -> activated (reason 'none', sys-iface-state: 'external')
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.0626] device (vpn001782c1f8): Activation: successful, device activated.
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.3451] audit: op="connection-update" uuid="80105f36-446d-4d91-99bd-a8ece752c6d7" name="fougeres" args="ipv4.ignore-auto-dns" pid=221215 uid=0 result="success"
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.3687] audit: op="connection-update" uuid="80105f36-446d-4d91-99bd-a8ece752c6d7" name="fougeres" args="ipv4.dns" pid=221220 uid=0 result="success"
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.3879] audit: op="connection-update" uuid="80105f36-446d-4d91-99bd-a8ece752c6d7" name="fougeres" pid=221225 uid=0 result="success"
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4050] audit: op="device-reapply" interface="wlo1" ifindex=2 args="ipv4.dns,ipv4.ignore-auto-dns" pid=221230 uid=0 result="success"
mai 15 20:34:05 tibook nm-dispatcher[221235]: /etc/NetworkManager/dispatcher.d/01-ifupdown: called with unknown action `reapply'
mai 15 20:34:05 tibook nm-dispatcher[221135]: req:3 'reapply' [wlo1], "/etc/NetworkManager/dispatcher.d/01-ifupdown": complete: failed with Script '/etc/NetworkManager/dispatcher.d/01-ifupdown' exited with status 1.
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4364] dhcp4 (wlo1): canceled DHCP transaction
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4364] dhcp4 (wlo1): activation: beginning transaction (timeout in 45 seconds)
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4364] dhcp4 (wlo1): state changed no lease
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4370] dhcp4 (wlo1): activation: beginning transaction (timeout in 45 seconds)
mai 15 20:34:05 tibook avahi-daemon[4244]: Withdrawing address record for fe80::a78d:f53f:ef19:1ef5 on wlo1.
mai 15 20:34:05 tibook avahi-daemon[4244]: Leaving mDNS multicast group on interface wlo1.IPv6 with address fe80::a78d:f53f:ef19:1ef5.
mai 15 20:34:05 tibook avahi-daemon[4244]: Interface wlo1.IPv6 no longer relevant for mDNS.
mai 15 20:34:05 tibook avahi-daemon[4244]: Joining mDNS multicast group on interface wlo1.IPv6 with address fe80::a78d:f53f:ef19:1ef5.
mai 15 20:34:05 tibook avahi-daemon[4244]: New relevant interface wlo1.IPv6 for mDNS.
mai 15 20:34:05 tibook avahi-daemon[4244]: Registering new address record for fe80::a78d:f53f:ef19:1ef5 on wlo1.*.
mai 15 20:34:05 tibook dnsmasq[8509]: reading /etc/resolv.conf
mai 15 20:34:05 tibook systemd-resolved[184505]: wlo1: Bus client reset search domain list.
mai 15 20:34:05 tibook dnsmasq[8509]: using nameserver 127.0.0.53#53
mai 15 20:34:05 tibook systemd-resolved[184505]: wlo1: Bus client set default route setting: no
mai 15 20:34:05 tibook dnsmasq[8509]: using only locally-known addresses for lxd
mai 15 20:34:05 tibook dnsmasq[8509]: reading /etc/resolv.conf
mai 15 20:34:05 tibook dnsmasq[8509]: using nameserver 127.0.0.53#53
mai 15 20:34:05 tibook dnsmasq[8509]: using only locally-known addresses for lxd
mai 15 20:34:05 tibook systemd-resolved[184505]: wlo1: Bus client reset DNS server list.
mai 15 20:34:05 tibook NetworkManager[4875]: <warn> [1684175645.4635] dispatcher: (21) /etc/NetworkManager/dispatcher.d/01-ifupdown failed (failed): Script '/etc/NetworkManager/dispatcher.d/01-ifupdown' exited with status 1.
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4684] dhcp4 (wlo1): state changed new lease, address=10.0.0.22
mai 15 20:34:05 tibook systemd-resolved[184505]: wlo1: Bus client set default route setting: yes
mai 15 20:34:05 tibook systemd-resolved[184505]: wlo1: Bus client set DNS server list to: 10.254.2.8, 192.168.100.40
mai 15 20:34:05 tibook plasmashell[13606]: kf.networkmanagerqt: void NetworkManager::ConnectionPrivate::onPropertiesChanged(const QVariantMap&) Unhandled property "Filename"
mai 15 20:34:05 tibook kded5[13159]: kf.networkmanagerqt: void NetworkManager::ConnectionPrivate::onPropertiesChanged(const QVariantMap&) Unhandled property "Filename"
mai 15 20:34:05 tibook kded5[13159]: kf.networkmanagerqt: void NetworkManager::ConnectionPrivate::onPropertiesChanged(const QVariantMap&) Unhandled property "Flags"
mai 15 20:34:05 tibook plasmashell[13606]: kf.networkmanagerqt: void NetworkManager::ConnectionPrivate::onPropertiesChanged(const QVariantMap&) Unhandled property "Flags"
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4847] audit: op="connection-update" uuid="d337717e-af5e-4281-a525-c735bf2acf27" name="vpn001782c1f8" args="ipv4.dns,connection.timestamp" pid=221236 uid=0 result="success"
mai 15 20:34:05 tibook NetworkManager[4875]: <info> [1684175645.4957] device (vpn001782c1f8): state change: activated -> unmanaged (reason 'connection-assumed', sys-iface-state: 'managed')
mai 15 20:34:05 tibook systemd-resolved[184505]: vpn001782c1f8: Bus client set default route setting: no
mai 15 20:34:05 tibook nm-dispatcher[221263]: /etc/NetworkManager/dispatcher.d/01-ifupdown: called with unknown action `reapply'
mai 15 20:34:05 tibook nm-dispatcher[221135]: req:5 'reapply' [vpn001782c1f8], "/etc/NetworkManager/dispatcher.d/01-ifupdown": complete: failed with Script '/etc/NetworkManager/dispatcher.d/01-ifupdown' exited with status 1.
与 22.04 VM 的成功连接日志给出：
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3507] manager: (vpn004e1bc85f): new Tun device (/org/freedesktop/NetworkManager/Devices/7)
mai 16 08:13:59 etabli22 systemd-udevd[3116]: Using default interface naming scheme 'v249'.
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3599] device (vpn004e1bc85f): state change: unmanaged -> unavailable (reason 'connection-assumed', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3602] device (vpn004e1bc85f): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3612] device (vpn004e1bc85f): Activation: starting connection 'vpn004e1bc85f' (cf5db700-b9ba-4a59-9d38-06b6c0414e34)
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3636] device (vpn004e1bc85f): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3638] device (vpn004e1bc85f): state change: prepare -> config (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3639] device (vpn004e1bc85f): state change: config -> ip-config (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3640] device (vpn004e1bc85f): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 dbus-daemon[700]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.11' (uid=0 pid=701 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
mai 16 08:13:59 etabli22 systemd[1]: Starting Network Manager Script Dispatcher Service...
mai 16 08:13:59 etabli22 dbus-daemon[700]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
mai 16 08:13:59 etabli22 systemd[1]: Started Network Manager Script Dispatcher Service.
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3731] device (vpn004e1bc85f): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3733] device (vpn004e1bc85f): state change: secondaries -> activated (reason 'none', sys-iface-state: 'external')
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.3736] device (vpn004e1bc85f): Activation: successful, device activated.
mai 16 08:13:59 etabli22 systemd-resolved[3005]: Using degraded feature set TCP instead of UDP for DNS server 10.254.2.8.
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.7613] audit: op="connection-update" uuid="d8162531-6770-3746-b7ff-57248dcf1521" name="Connexion filaire 1" pid=3194 uid=0 result="success"
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.7827] audit: op="connection-update" uuid="d8162531-6770-3746-b7ff-57248dcf1521" name="Connexion filaire 1" pid=3198 uid=0 result="success"
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.8009] audit: op="connection-update" uuid="d8162531-6770-3746-b7ff-57248dcf1521" name="Connexion filaire 1" pid=3202 uid=0 result="success"
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.8127] audit: op="device-reapply" interface="enp0s3" ifindex=2 pid=3206 uid=0 result="success"
mai 16 08:13:59 etabli22 NetworkManager[701]: <info> [1684217639.8310] audit: op="connection-update" uuid="cf5db700-b9ba-4a59-9d38-06b6c0414e34" name="vpn004e1bc85f" args="ipv4.dns" pid=3210 uid=0 result="success"
mai 16 08:13:59 etabli22 systemd-resolved[3005]: vpn004e1bc85f: Bus client set default route setting: no
mai 16 08:13:59 etabli22 systemd[1]: Stopping Network Name Resolution...
mai 16 08:13:59 etabli22 systemd[1]: systemd-resolved.service: Deactivated successfully.
mai 16 08:13:59 etabli22 systemd[1]: Stopped Network Name Resolution.
mai 16 08:13:59 etabli22 systemd[1]: Starting Network Name Resolution...
mai 16 08:13:59 etabli22 systemd-resolved[3219]: Positive Trust Anchors:
mai 16 08:13:59 etabli22 systemd-resolved[3219]: . IN DS 20326 8 2 e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d
mai 16 08:13:59 etabli22 systemd-resolved[3219]: Negative trust anchors: home.arpa 10.in-addr.arpa 16.172.in-addr.arpa 17.172.in-addr.arpa 18.172.in-addr.arpa 19.172.in-addr.arpa 20.172.in-addr.arpa 21.172.in-addr.arpa 22.172.in-addr.arpa 23.172.in-addr.arpa 24.172.in-addr.arpa 25.172.in-addr.arpa 26.172.in-addr.arpa 27.172.in-addr.arpa 28.172.in-addr.arpa 29.172.in-addr.arpa 30.172.in-addr.arpa 31.172.in-addr.arpa 168.192.in-addr.arpa d.f.ip6.arpa corp home internal intranet lan local private test
mai 16 08:13:59 etabli22 systemd-resolved[3219]: Using system hostname 'etabli22'.
mai 16 08:13:59 etabli22 systemd[1]: Started Network Name Resolution.