XTM25 dropping WAN connections every 15 minutes?

I could use some help getting to the bottom of a weird (at least to me) network problem, and please indulge the lengthy description—I want to make sure I provide enough background info and context.

I’ve got an XTM25 configured with Multi-WAN, Interface Overflow.
I’ve also got a number of users that connect to hosted QuickBooks on Right Networks, which uses RDP.

Somewhere around six weeks ago, it was brought to my attention that my Quickbooks users were frequently getting “kicked out” of Right Networks. My investigation led me to discover that what they were experiencing was a brief interruption in the RDP connection—maybe just 30 seconds or so, if that—and then the connection would reestablish itself, though the user had to re-enter their password each time this happened, presumably due to the way the RDP server is configured.

At first I chalked this up to transient issues or random glitches, but I was told by the one person who pretty much spends all day in this RDP connection, that the connections were very frequent and occurred “dozens” of times per day.
I happen to work remotely a lot and use Splashtop to remotely access various PCs on the LAN. In roughly the same timeframe that my QB users’ problems began, I started noticed that my Splashtop connections were frequently interrupted. Same symptom—connection would become unresponsive for 30 seconds or so, and then it would be back again.

It took me a little while to realize this, but I’ve discovered that my disconnects and the users’ disconnects always occur at the same time. Not only that, but they are happening every 15 minutes on a predictable schedule, at 13, 28, 43, and 58 minutes past each hour.

Bottom line, as best as I can tell, all inbound and outbound WAN connections are getting dropped every 15 minutes like clockwork, and I don’t know why. The XTM configuration has not been changed recently—not in years, actually) to cause a problem like this.

I logged into the XTM and pulled the Traffic monitor logs (which overwrite every 17 minutes so it’s capturing the outage time), but I’m not experienced enough to see any obvious problem or smoking gun.

If anyone has any thoughts on what might be going on here or what I can check, I would be very grateful.

Thanks very much.



  • Options

    For the record, what XTM version is on your XTM25 ?

    Check the incoming & outgoing bandwidth on the primary WAN link at the problem times. If the either becomes near 100% saturated, you could experience dropped packets and thus session timeouts.

    With Interface Overflow, new outgoing connections will only go out the 2nd WAN when the primary has reached the bandwidth threshold. Existing connections started on the primary will not use the 2nd WAN ever (true for any Multi-WAN method).

    If it ends up being a bandwidth issue, you can set up Traffic Management to try to address the issue - prioritize selected traffic; guarantee minimum bandwidth for selected policies; limit the max bandwidth used for selected traffic.

  • Options

    Thank you for the response, Bruce.

    Apologies for not including the XTM version; it is 11.12.2. Also, I accidentally typoed the hardware model in my OP-- it's an XTM26, not a XTM25.

    I watched the XTM's bandwidth meter over the course of several of these incidents, which are still occurring like clockwork four times an hour, and at the same times each hour. The WAN link (which is fiber, 100 Mbps in each direction) never comes anywhere close to saturation when the sessions are timing out.

    It's occurred to me that this issue could possibly be caused by an issue with my WAN provider, but I've tried continuously pinging the WAN provider's gateway IP during the timeout periods and there are no drops or even latent responses. Don't know if that necessarily proves or disproves anything, though, and I'd like to rule out an issue with the XTM before I go down that road.

    To that end, I was next going to try swapping the Primary and Secondary WAN connections in Multi-WAN to see if that changes the behavior?

    Also, the XTM uptime is 865 days, so, a pretty long time. Would a restart be prudent?

    Do you have any other suggestions in lieu or in addition to the above that might help get to the bottom of this?

    Many thanks.


  • Options

    So I swapped the primary and secondary WAN connections in the XTM config and the problem went away. That's not a permanent fix b/c I replaced a 100/100 fiber connection with a 85/15 cable modem, but it will serve as a workaround while I take this up with my primary WAN provider.

Sign In to comment.