@dennis100 ah if your clients can not do it? Then you have a bit of a problem.. But that is something you would want to implement because it keeps noise away from your vpn.. Only authorized clients to actually even start a conversation with your vpn, etc.
But I find it hard to believe the viscosity client could not do that.. Its basic openvpn stuff.. Maybe not do tls-crypt, but they should be able to do at min tls-auth
edit: so quick google found this, so there might of been a problem with older client, but looks like from that that the viscosity client should for sure support tls-crypt
https://www.sparklabs.com/forum/viewtopic.php?t=2647
Here is tls-auth I found on their site. So clearly they support it, you would just need to set it up
https://www.sparklabs.com/support/kb/article/advanced-configuration-commands/#tls-auth
Add an additional layer of HMAC authentication on top of the TLS control channel to mitigate DoS attacks and attacks on the TLS stack.
In a nutshell, tls-auth enables a kind of "HMAC firewall" on OpenVPN's TCP/UDP port, where TLS control channel packets bearing an incorrect HMAC signature can be dropped immediately without response.