SSL VPN went down when try RDP connection

MatteoPSC
MatteoPSC Posts: 3  Zyxel Employee
First Anniversary Friend Collector First Comment
edited April 2021 in Security
Hello!
I have an USG20-VPN with latest fw (4.60 (ABAQ.1))
I have 2 SSL connection with SecuExtender 4.0.3.0. One with Win10 with no problems. RDP work fine.
The one with Win8.1 went down when try to open RDP.
I try with another pc the same configuration and work.
I try to update every driver with DVRHUB. I try to change MTU into th TAP adapter with the values 1370, 1392, 1400 but still the same problem.
In the USG20-VPN log the error is "SSL tunnel receives a packet with invalid packet size."
I think that's an Win8.1 issue. What can I do?
Thank you!

All Replies

  • Zyxel_Jeff
    Zyxel_Jeff Posts: 1,059  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer
    “The one with Win8.1 went down when try to open RDP.”
    =>Do you mean that the SSL VPN connection can’t be established or the VPN can connect but the RDP connection failed? Can you ping to the RDP IP successfully? Or you can check the RDP side configuration, too.
  • MatteoPSC
    MatteoPSC Posts: 3  Zyxel Employee
    First Anniversary Friend Collector First Comment
    edited January 2021

    The SSL VNP went up perfectly. Ping work. When I try to open RDP connection after few seconds the VNP fall down.
    I try the same configuration and user on other 2 PC's and everything work fine.
    When I click on "connect" in RDP it start, work fews seconds, VPN fall down but rdp still try to connect. If I look in the log of the FW the red error appear: "SSL tunnel receives a packet with invalid packet size."
    In other forum people say that's MTU but is wierd that in other PC's everything works. the only difference is Win8.1 instead Win10.
    If I don't open RDP the VPN won't fall down.
  • kukuman
    kukuman Posts: 16  Freshman Member
    First Anniversary Friend Collector First Comment
    @MatteoPSC

    The only difference is windows OS version.
    SSL VPN connection drop happened when you using RDP  on Win8.1  but win 10 can't.
    Did you consult with Microsoft for further suggestion? 
  • MatteoPSC
    MatteoPSC Posts: 3  Zyxel Employee
    First Anniversary Friend Collector First Comment
    kukuman said:
    @MatteoPSC

    The only difference is windows OS version.
    SSL VPN connection drop happened when you using RDP  on Win8.1  but win 10 can't.
    Did you consult with Microsoft for further suggestion? 

    I found this. I need to try asap.

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