Network stops after disconnecting from VPN

Hardware Support
1

I'm having an issue with Zorin (17.2) and regaining network access after coming out of VPN. I use Cisco AnyConnect to connect to my work computer. Prior to launching it I can connect to the Internet fine. Same with after starting AnyConnect. However when I disconnect from AnyConnect I can no longer access the Internet and the only way to fix it is to reboot.

To test if this is Zorin specifically our Linux in general I ran a test using Mint Live and once I disconnect AnyConnect the internet comes back up no problem, so I assume this is something Zorin related.

I'm on the network via cable and not wireless. It's an Intel-based chipset. Does anyone have thoughts on how to fix this? Rebooting Zorin every time is a pain. Thanks.

2

I can't say I know this VPN at all. Does it have a kill switch option that disables your Internet connection when the connection through the VPN stops? Sometimes that gets enables on accident and can cause something like this.

3

No it doesn't.

4

Hello,
after disconnecting from AnyConnect, what do you have with :

tcpdump --list-interfaces
5

It's not a public, general use VPN; it's a B2B product Cisco offers corporations to enable access to corporate networks. I use it myself, but only on Windows. (Work would hang me from a chandelier if I were caught connecting a personal device.)

2 Likes
6 
1.enp3s0 [Up, Running, Connected]
2.any (Pseudo-device that captures on all interfaces) [Up, Running]
3.lo [Up, Running, Loopback]
4.bluetooth-monitor (Bluetooth Linux Monitor) [Wireless]
5.nflog (Linux netfilter log (NFLOG) interface) [none]
6.nfqueue (Linux netfilter queue (NFQUEUE) interface) [none]
7.dbus-system (D-Bus system bus) [none]
8.dbus-session (D-Bus session bus) [none]
7

could you try that after disconnecting from Anyconnect :

echo 1  | sudo tee /sys/bus/pci/rescan
8

It just has the number 1.

9

Check DNS Settings : Sometimes, the VPN client can alter your DNS settings, which may not revert correctly after disconnecting. You can try resetting your DNS settings manually. Open a terminal and run:

sudo resolvconf -u

If this command is not found, you can manually edit the /etc/resolv.conf file to include a valid DNS server, such as:

nameserver 8.8.8.8
nameserver 8.8.4.4

Restart Network Services: Restarting the network services can sometimes resolve connectivity issues. You can do this by running:

sudo systemctl restart NetworkManager
10

Well I don't know what happened but now it's suddenly working. If anything thing changes I'll let you know. Appreciate the assistance.

1 Like
11

Maybe an update, I had one of NetworkManager today...

12

Yes, Cisco AnyConnect may enforce a kill switch-like feature that blocks internet access after disconnection-check its settings or restart Network Manager to restore connectivity.

1 Like