Support Forum
The Forums are a place to find answers on a range of Fortinet products from peers and product experts.
New Contributor

Flush DNS cache failed and Backup routing table failed on Ubuntu 20.04

I am able to establish a VPN connection, but I immediately get disconnected from the VPN a few seconds later. I believe that connecting to the VPN is causing my WiFi to disconnect, but I am not sure if this is what's actually happening.


I am on Ubuntu 20.04.6. I downloaded the Debian client directly from the Fortinet website. I have been able to connect to the VPN fine on Windows/Mac computers, so I don't think it's an issue authentication issue, especially since I am passing the authentication phase on the Linux.


So far, I have tried to disable IPv6 and the local Ubuntu firewall, but I am still experiencing the same issue.


Here are the device logs showing the errors for "Flush DNS cache failed" and "Backup routing table failed"

20230405 21:01:00.765 [sslvpn:DEBG] dns:149 Restart DNS service successfully.
20230405 21:01:00.767 [sslvpn:DEBG] dns:161 Flush DNS cache failed.
20230405 21:01:00.767 [sslvpn:DEBG] route:99 route backup START
20230405 21:01:00.767 [sslvpn:DEBG] route:109 No gateway found for
20230405 21:01:00.767 [sslvpn:DEBG] route:127 No gateway found for [VPN IP]
20230405 21:01:00.767 [sslvpn:DEBG] route:151 route backup DONE
20230405 21:01:00.767 [sslvpn:EROR] vpn_connection:1296 Backup routing table failed



Which version of FortiClient? Which version of FortiOS? Are you doing split tunnel or full tunnel?


Select Forum Responses to become Knowledge Articles!

Select the “Nominate to Knowledge Base” button to recommend a forum post to become a knowledge article.

Top Kudoed Authors