Can't connect to IPsec VPN in Windows 11

[jfbueno]

I wasn't able to connect to an IPsec VPN through FortiClient VPN (7.0.2.0090 free) when updated to Windows 11 (build 22000), SSL VPNs were working fine. When I downgraded to Windows 10 (21h2 build 19044.1415) the IPsec VPN started working again.

This is the error that I got on FortiClient

 

And this is the log that I exported

12/28/2021 4:02:55 PM	info	sslvpn	date=2021-12-28 time=16:02:54 logver=1 id=96602 type=securityevent subtype=sslvpn eventtype=status level=info uid=19AEBE88942A48F59578C42AA765D590 devid=FCT8003159070034 hostname=DESKTOP-5BJFTJ3 pcdomain=N/A deviceip=192.168.224.1 devicemac=<redacted> site=N/A fctver=7.0.2.0090 fgtserial=FCT8003159070034 emsserial=N/A os="Microsoft Windows 11 , 64-bit (build 22000)" user=bueno msg="SSLVPN service started successfully" vpnstate=

12/28/2021 4:03:04 PM	info	system	date=2021-12-28 time=16:03:03 logver=1 id=96823 type=systemevent subtype=system eventtype=status level=info uid=19AEBE88942A48F59578C42AA765D590 devid=FCT8003159070034 hostname=DESKTOP-5BJFTJ3 pcdomain=N/A deviceip=192.168.224.1 devicemac=<redacted> site=N/A fctver=7.0.2.0090 fgtserial=FCT8003159070034 emsserial=N/A os="Microsoft Windows 11 , 64-bit (build 22000)" user=bueno msg="Checking for updates"

12/28/2021 4:04:26 PM	info	ipsecvpn	date=2021-12-28 time=16:04:25 logver=1 id=96566 type=securityevent subtype=ipsecvpn eventtype=status level=info uid=19AEBE88942A48F59578C42AA765D590 devid=FCT8003159070034 hostname=DESKTOP-5BJFTJ3 pcdomain=N/A deviceip=192.168.224.1 devicemac=<redacted> site=N/A fctver=7.0.2.0090 fgtserial=FCT8003159070034 emsserial=N/A os="Microsoft Windows 11 , 64-bit (build 22000)" user=bueno msg="loc_ip=192.168.100.2 loc_port=500 rem_ip=<vpn-external-ip> rem_port=500 out_if=0 vpn_tunnel=RS IPsec action=negotiate init=local mode=aggressive stage=1 dir=outbound status=success Initiator: sent <vpn-external-ip> aggressive mode message #1 (OK)" vpntunnel="RS IPsec"

12/28/2021 4:04:38 PM	warning	ipsecvpn	date=2021-12-28 time=16:04:37 logver=1 id=96561 type=securityevent subtype=ipsecvpn eventtype=error level=warning uid=19AEBE88942A48F59578C42AA765D590 devid=FCT8003159070034 hostname=DESKTOP-5BJFTJ3 pcdomain=N/A deviceip=192.168.224.1 devicemac=<redacted> site=N/A fctver=7.0.2.0090 fgtserial=FCT8003159070034 emsserial=N/A os="Microsoft Windows 11 , 64-bit (build 22000)" user=bueno msg="No response from the peer, phase1 retransmit reaches maximum count" vpntunnel="RS IPsec" locip=192.168.100.2 locport=500 remip=<vpn-external-ip> remport=500

This is a log exported after a successful connection (in W10)

12/30/2021 8:24:23 AM	info	ipsecvpn	date=2021-12-30 time=08:24:22 logver=1 id=96566 type=securityevent subtype=ipsecvpn eventtype=status level=info uid=19AEBE88942A48F59578C42AA765D590 devid=FCT8003159070034 hostname=DESKTOP-5BJFTJ3 pcdomain=N/A deviceip=<my-external-ip> devicemac=<redacted> site=N/A fctver=7.0.2.0090 fgtserial=FCT8003159070034 emsserial=N/A os="Microsoft Windows 10 , 64-bit (build 19041)" user=bueno msg="loc_ip=192.168.100.2 loc_port=4500 rem_ip=<vpn-external-ip> rem_port=4500 out_if=0 vpn_tunnel=CIEE-RS action=negotiate init=local mode=quick stage=2 dir=outbound status=success Initiator: sent <vpn-external-ip> quick mode message #2 (DONE)" vpntunnel=CIEE-RS

In this log the loc_port and rem_port are different (4500, in the other log it's 500), also the deviceip is my external IP, not a local IP (that doesn't look like an IP that my machine would be using).

I don't know if that's causing the problem, but it's all I can find.

Does anyone have any tips?

[SkepticSensei]

Downgrade your Ethernet driver to a windows 10 driver.

That worked for me.

[armandoa]

I have the same problem. It seems to be a problem with windows 11. Any update? Thanks.

[SkepticSensei · Accepted solution]

I figured out the issue. It is a Windows 11 Ethernet driver issue. 

Wifi connects to VPN, Ethernet via USB to Eth adapter works. 

I downgraded to Win10 Realtek 10.54 driver version.

That fixed the issue for me.

Realtek PCIe FE / GBE / 2.5G / Gaming Ethernet Family Controller Software - REALTEK

let me know if this works for anyone else. 

[jfbueno]

I updated the same machine, got the same problem and this hack really solved it. Thank you!

[Charles77]

Thank you so much! My desktop at home stopped connecting to our VPN after installing the Windows 11 22H2 update. I knew it was something PC-specific since my Dell laptop on WiFi would still connect. The driver downgrade did the trick!! Appreciate the assistance.

[goneriding]

Worked for me as well

[theo2f]

Before this answer, the only way I could connect to the VPN was via WI-FI, because cable didn't work.
After using the Windows 10 driver, in addition to connecting, the speed is MUCH FASTER.
Thank you very much!

[divad]

Thank you, it worked on our Windows 11 system. i also downgraded to an older driver on the Realtek ethernet controller.

[VincentCA]

I'm getting this error, but I don't have a Realtek driver. Any suggestions?

[BillWabo]

Hello, what is the brand of your network adapter? Wi-fi or ethernet?