AnyConnect Disconnected Autiomatically

[Kelvin_]

Hi guys,

I am trying to connect a remote server through AnyConnect VPN in my Ubuntu 19.10, but it always get disconnected after connected for dozens of minutes. I tried to connect in my Macbook, it worked fine. The syslog logged the time when VPN was disconnected and shown below. Can any help?

Feb 23 14:13:26 kelvin openconnect[8887]: Received server disconnect: b0 'Idle Timeout'
Feb 23 14:13:26 kelvin openconnect[8887]: Send BYE packet: Server request
Feb 23 14:13:26 kelvin NetworkManager[1096]: <info>  [1582438406.8787] device (vpn0): state change: activated -> unmanaged (reason 'unmanaged', sys-iface-state: 'removed')
Feb 23 14:13:26 kelvin openconnect[8887]: Session terminated by server; exiting.
Feb 23 14:13:26 kelvin gnome-shell[1764]: Removing a network device that was not added
Feb 23 14:13:26 kelvin dbus-daemon[927]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.21' (uid=0 pid=1096 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
Feb 23 14:13:26 kelvin systemd[1]: Starting Network Manager Script Dispatcher Service...
Feb 23 14:13:26 kelvin dbus-daemon[927]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Feb 23 14:13:26 kelvin gnome-shell[1764]: JS ERROR: TypeError: connectionSettings is null#012_updateConnection@resource:///org/gnome/shell/ui/status/network.js:1922:9
Feb 23 14:13:26 kelvin systemd[1]: Started Network Manager Script Dispatcher Service.
Feb 23 14:13:26 kelvin NetworkManager[1096]: <info>  [1582438406.9454] vpn-connection[XXXXXXXXXXX,XXXXXXXXXXXXXXXXXXXXXXXXXX,"CSVPN",5:(vpn0)]: VPN service disappeared
Feb 23 14:13:32 kelvin systemd-resolved[881]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
Feb 23 14:13:42 kelvin systemd[1]: NetworkManager-dispatcher.service: Succeeded.

[Sheraz.Salim]

What’s are the ildle timeout setting you setup? Could you share the configuration of your ASA.

show run tunnel-group

[Kelvin_]

Thank you for your help. As I do not own the ASA, I am not able to give you the configuration. I am wondering if it is my computer's problem or the service provider's problem.

[Marius Gunnerud]

Try lowering the MTU on your interface to 1200.

[Kelvin_]

I am not sure I do it in the right way. I use "sudo ip link set vpn0 mtu 1200" to set MTU, but it is still not working.

$sudo ip link show
9: vpn0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1200 qdisc fq_codel state UP mode DEFAULT group default qlen 500
    link/none

[Marius Gunnerud]

I was thinking more along the lines of changing the MTU on the physical interface you are using for network connectivity, be it an ethernet port or wireless.

https://www.cyberciti.biz/faq/centos-rhel-redhat-fedora-debian-linux-mtu-size/

[Kelvin_ · Accepted solution]

I tried to re-establish the network and reinstall the VPN and set up the whole thing again. It works fine now. Anyway, I really appreciate your help.