Backup DNS Failed in Ubuntu 22.04

Hello

Probably it failed to backup your DNS context before injecting VPN's DNS server IP (?)

Try check which DNS servers is your client using before and after VPN connection, and after VPN disconnection, to see if it is updated as expected.

Hello @NARTONIC 

you can also check this discussion .

regards,

Sheikh

I faced the same issue:

sudo tail -f   /var/log/forticlient/sslvpn.log :

20231209 18:05:50.952 TZ=+0200 [sslvpn:DEBG] vpn_connection:1349 Login process end on status: 0
20231209 18:05:50.952 TZ=+0200 [sslvpn:INFO] sslvpn:824 Login successful
20231209 18:05:50.998 TZ=+0200 [sslvpn:INFO] main:1456 State: Configuring tunnel
20231209 18:05:51.068 TZ=+0200 [sslvpn:DEBG] vpn_util:260 Get connection name: ????????? ?????????? 1
20231209 18:05:51.068 TZ=+0200 [sslvpn:DEBG] vif:98 Using nmcli to allocate tun device.
20231209 18:05:51.367 TZ=+0200 [sslvpn:DEBG] dns:274 Default route device name: enxc8f750b40f75
20231209 18:05:51.430 TZ=+0200 [sslvpn:DEBG] vpn_util:260 Get connection name: ????????? ?????????? 1
20231209 18:05:51.430 TZ=+0200 [sslvpn:DEBG] dns:286 DNS backup
20231209 18:05:51.496 TZ=+0200 [sslvpn:DEBG] vpn_util:234 Get auto DNS setting failed.
20231209 18:05:51.496 TZ=+0200 [sslvpn:EROR] vpn_connection:1634 Backup DNS failed

I got this error as well, using version 7.2.2.0753 on 22.04.3 LTS.

Changing Wi-Fi networks worked for me. I don't know why that is, but it worked. I tethered to my phone and it worked, as did switching to my guest network.

The latter really doesn't make sense to me, but I'm not very knowledgeable in this area.

It's not possible that there's an issue with the network names or something, right? The one that doesn't work has a colon in it? Sounds like a bad idea but getting it on screen anyways.

I had this problem for a couple of days, checking the logs I have found that my connection name was with strange characters replacing the accents and spaces, the original name in Spanish was "Conexión Cableada 2", I changed it to "cableate" and voilà, it worked as expected!! I hope this comment helps you to solve your problem.... good luck!!

UPDATE to clarify some stuff that may not be well explained...

By "my connection" I mean the connection from my computer to my internal network/router, in my case is a network cable connection.

If you have problems while connected to a WI-FI connection, so the SSID (the name of the wi-fi connection) may be the problem; check that the SSID has no accents or spaces...

The root cause is not really the Wi-Fi network itself, but the name of the connection that Ubuntu passes to FortiClient. If the SSID or connection name contains spaces, accents, or special characters, FortiClient sometimes fails when trying to backup DNS, producing the error “Backup DNS failed”.

Since sometimes you cannot change the Wi-Fi SSID, the best workaround is to rename the connection locally in Ubuntu (this is different from the router SSID).

You keep the same SSID but change the connection profile name.

From the GUI :

1. Open Settings ---> Wi-Fi

2. Click the gear icon of your network.

3. Change Name from something like: My WiFi:Company to  something simple like wifi_company

4. Disconnect and reconnect.

FortiClient will now read the profile name, not the SSID.