Description
This article describes a DNS issue with FortiClient SSL VPN when IPv6 is enabled on the endpoint network adapter.
Scope
FortiClient.
Solution
SSL VPN does not support dual-stack IPv4/IPv6.
When IPv6 is enabled on the endpoint network adapter. Windows always prefers IPv6 over IPv4.
Issues may be faced where the IPv6 address and route are not being received.
Within the FortiClient XML configuration file, verify the value for blocking IPv6.
<block_ipv6>1</block_ipv6>
<forticlient_configuration>
<vpn>
<sslvpn>
<options>
<block_ipv6>1</block_ipv6>
Related document:
SSL VPN
Set the block IPv6 setting to '1', so FortiClient blocks the IPv6 connection. FortiClient uses only IPv4 connectivity when the SSL VPN tunnel is up.
