Issue with FortiGate 100E Firewall: Error Code 502 During VPN Configuration

[Emma02]

Hi everyone,

I'm currently experiencing an issue with my FortiGate 100E firewall while trying to configure a site-to-site VPN connection. Every time I attempt to set up the IPsec tunnel, I receive an "Error Code 502: Bad Gateway" in the management console.

I'm using FortiOS 6.2.3, and the exact error message is as follows:

Error Code 502: Bad Gateway - The remote server returned an error while processing the configuration request.

I have tried rebooting the device, resetting the VPN settings, and updating to the latest firmware, but the problem persists. The configuration was working properly with a different model, so I'm unsure what might be causing this issue with the 100E.

Has anyone else encountered this problem or have any suggestions on how to resolve it? Your insights would be greatly appreciated.

Thanks in advance,

[Emma02]

Thanks Eden for this answer. 

[xsilver_FTNT]

Hi Emma02,

just friendly reminder that FortiOS 6.2 is going out of support AND 6.2.3 a pretty old version too!

Have a look to Product LifeCycle - https://support.fortinet.com/Information/ProductLifeCycle.aspx

Support will end on 2023-09-28.

FortiOS 6.2.3 is, almost to this day, 3 years old. Which is IMHO in always evolving threat landscape and network security is a lot.
Therefore should you want, for whatever reason, stay on 6.2, then I'd surely recommend to have a look at 6.2.15 - your 100E is still supported there.
https://docs.fortinet.com/document/fortigate/6.2.15/fortios-release-notes/760203/introduction-and-su...

If you are not a big fan of version 7, then consider 6.4 which does have support till 2024-09-30.

Sure, we will try to help here, but in official TAC ticket you might be asked by support to upgrade to supported version. Plus, flaws and possible vulnerabilities of older versions are fixed in new ones. So upgrade might be a "must have" to get a fixed version.