SSL-VPN clients randomly disconnect

With all my users working remotely now my SSL-VPN users have been having random disconnects (It connects again within a couple seconds) Doesn't happen when only a few are on but when most of the users are on. Read something about the MTU setting in relation to this. We have Comcast Fiber Optic going to our Watchguard M370 (Running 12.5.B597646 Fireware) Has anyone else had a similar issue? I have an open ticket with support but it's been two days and nothing but the original tech escalated it.


  • James_CarsonJames_Carson WatchGuard Representative

    Hi @engsoft

    MTU is usually only an issue when you're sending data across an interface that has a lowered MTU (like a DSL line.) So long as the ISP's value is the default, 1500, you should be set there.

    I'd suggest trying the latest firmware, and also making sure the client's SSLVPN client is up to date.

    If the issue persists, consider opening a support case. I'd suggest collecting the following info:
    -Is this happening on some clients, or all of them. If just some, what ISPs and type do the customers have? (e.g., comcast, cable modem; BellSouth, DSL.)

    -What version of the SSLVPN client are they using?

    -How is the user authenticating? (Active Directory, RADIUS, Firebox-DB)

    -Do any errors appear on the client program or on the firewall's traffic monitor related to the connection?

    Thank you,

    -James Carson
    WatchGuard Customer Support

  • We're experiencing something very similar to this. From what I can tell the disconnects happen every 22 minutes. Does that sound similar?

    No errors in the logs. I'll open a support case.

  • I resolved this by switching the data channel to UDP in the advanced settings. Users have been stable ever since.

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