May 07, 2020 · 4.2 Configure Port Following for IKEv2 UDP Virtual Services. Port Following is required to ensure connections for IKEv2 UDP 500 and 4500 are sent to the same Real Server. To configure Port Following, see the following sections. For more information, see the Port Following document on the Kemp documentation page.
Jul 22, 2020 Using VPN over TCP 80, 443 and UDP 53,2049? - Information The port you choose doesn't affect the security of the VPN. Using different ports only helps to avoid/bypass firewall rules. Of course if network administrators inspect your traffic they'll detect that you're using a different protocol than the usual for that specific port (f.e. HTTP for port 80). How to Enable VPN Passthrough - IPsec Firewall Port - Tom May 20, 2003
For L2TP/IPSEC VPN connections, you need to open UDP port 500 for Internet Key Exchange (IKE) traffic, UDP port 4500 (IPsec control path) and UDP port 1701 for L2TP traffic. IPsec ESP traffic also uses IP protocol 50. SSTP connections use TCP port 443 (SSTP traffic to/from the VPN server)
For L2TP/IPSEC VPN connections, you need to open UDP port 500 for Internet Key Exchange (IKE) traffic, UDP port 4500 (IPsec control path) and UDP port 1701 for L2TP traffic. IPsec ESP traffic also uses IP protocol 50. SSTP connections use TCP port 443 (SSTP traffic to/from the VPN server) Why does VPN IPSec client use UDP? - Server Fault
Microsoft Always On VPN – Kemp Support
What port does VPN use?