Random internet outages - cable modem, pfSense or both to blame?



  • Hey guys,

    I'll start off by saying that I'm by no means a networking expert, but know enough to be dangerous.

    I built a pfSense box in December using the SuperMicro Atom 2758 board and loaded it up with 8GB RAM and a SSD.  pfSense is running an OpenVPN client (PIA) and Snort.  There are a handful of NAT rules, and I have two devices bypassing the VPN connection via NAT LAN rules.  I have a Netgear R7000 running as my wireless AP behind the pfSense box.  That's it really, pretty basic.  The main reason for pfSense for me was to get the fastest possible OpenVPN throughput.

    Shortly after building the box I started to get random cases where internet access would drop.  On the pfSense dashboard, the WAN IP address is empty/blank (no text at all, not even 0.0.0.0) when this happens.  I had suspicions that my ISP (TWC) might be doing something goofy since I was now running through a VPN 24/7, but even after I disabled that (and Snort), I'm still seeing it drop.

    My natural reaction is to blame the pfSense box because I've never had a problem with my modem for about 3 years since I received it.  Another lockup happened this morning and I finally went in to grab the modem log and found two log entries that indicated that the modem reboot itself - one for a T4 timeout and another for a power reset.  I called TWC and they were completely useless because I'm not using their modem.  There are lots of things on the internet about Motorola modems (mine is a SB6141) having T3/T4 reset issues on TWC, so this issues doesn't sound rare.

    When I first built my pfSense box, I did notice that if my modem was on and "ready" (after all LEDs settle), if I turned on the pfSense box, I would not get a WAN IP from the modem.  In short - it seems that pfSense needs to be up and running first, and the modem has to be up and "ready" before I connect the ethernet cable between the two.  I'm wondering if I've been having these modem issues all along only my R7000 was better able to handle the modem resetting than pfSense.  Like I said, if I reboot my modem without disconnecting the ethernet cable, I never see a WAN IP in my pfSense dashboard.

    At this point I'm considering buying a new modem (not Motorola/Arris), but would like to see if anybody else has had a similar issue or if there's a way to get pfSense to get its WAN IP without disconnecting the cable modem when it boots up.



  • Turns out it was indeed the modem.  I found out that my ISP had upgraded my speed for free, so needed to buy a new modem anyway.  Haven't had an issue in a week since the new modem has been installed.  pfSense is also able to get a WAN IP from the modem every time now without unplugging the ethernet cable.



  • Which modem did you buy?



  • I ended up getting the Netgear CM500-100NAS.



  • Thanks.

    I'll keep an eye on internet connection.