VPN has trouble connecting with the remote Gateway...

[#1]

Hi Everyone, I would like to ask for your help regarding errors we have encounter on our server while trying to connect to VPN using FortiClient. Found these errors while trying to connect on the VPN: By the way, our FortiClient version is 4.2.0.250 Thanks in advance.

[Jan_Scholten]

use new version of forticlient, check whether ipsec ist going through, enable NAT Traversal. debug on jade datacenter site.

[L_FTNT]

What' s FortiGate version? Were you able to connect to the fortigate before?

[#4]

I tried installing same version of FortiClient with other PC connected with separate network and I successfully connected with Jade datacenter using VPN. But still the server of our client experienced the same problem shown on above screenshots. They say all ports 500 and 1500 already set to PASS ALL. What might be the cause of the problem why on our client' s server experience the error and when I tried on the other PC FortiClient successfully connected?

[ede_pfau]

- have you enabled ' NAT traversal' in your FC' s config? - do you have a personal firewall software installed on this PC? When encountering NAT, the VPN client will use UDP encapsulation with ports UDP/500 and UDP/4500 (not 1500). If not, it will use plain AH and ESP - protocols different from TCP or UDP. To rule out that your router blocks this kind of traffic, do your PC and the other, working PC use the same device facing the internet?

[#6]

- have you enabled ' NAT traversal' in your FC' s config? What is that ' NAT traversal' ? How can I check if it is? - do you have a personal firewall software installed on this PC? If there is a personal firewall software installed? What needs to be consider? Regarding ports - yeah sorry for type error but what I really mean is ports 500 and 4500 UDP.

[ede_pfau]

' NAT traversal' is a setting in the FortiClient configuration that you have to check OK in order to be able to reach gateways behind (NAT) routers. If in doubt, enable this option anyway. Personal firewall (including the Windows firewall) may block your traffic if it doesn' t allow traffic other than TCP, UDP or ICMP. To test, disable any software firewall on your PC.

[L_FTNT]

Dennis, The following troubleshooting steps may help to pinpoint the cause of the issue. - Step 1: Eliminate the configuration as the cause of the issue 1. Export a working VPN connection from a workstation 2. Import the configuration file to the FCT on the server that has the problem 3. Connect the VPN tunnel on the server If you still cannot connect, that means the client configuration is not the cause for the issue and something on the server leads the connection fail. - Step 2: Eliminate the firewalls as the cause of the issue a) Turn off all the firewall both Windows and FCT b) Reconnect the tunnel again If you still cannot connect, that means the firewalls is not the culprit. - Step 3: Eliminate the Proxy conflicts a) Go to General -> Help & Support, click ' Diagnostics' b) Uncheck ' Enable FortiProxy' and OK c) Reconnect the VPN again to see if that fix your problem. If you still cannot connect, I will provide you more troubleshoot steps :).. Regards, L.C.

[#9]

Wow...Thanks for this sir. Will let you now if these would work.