How to manage LTE USB modem disconnect,reconnect and avoid crashing OPNsense

[GiantJack]

Hi There!

I have setup my OPNsense with 2 gateways: main (default) one is a DSL modem.
The second one is an LTE USB modem e3372h (hilink mode).

The LTE gateway helps to speed up a bit my not very fast DSL.
Both gateway works fine.

But I still face a couple of issues:

1- I may want to take the USB modem with me sometime (holidays, business trip...)

If I just take the modem out of the USB port of OPNsense =>  It does crash OPNsense !!
DHCP is dead, ping give no answer....all I can do is a reboot!

How can I avoid this ?

I would have expected that OPNsense should just set offline my LTE gateway...


2- This e3372h Hilink modem need to do a "usb_modeswitch" command when reconnected to the gateway.

I was thinking I could maybe "cron-ize" the command every five minute (it will just get with error message if the modem is always switched)...But that sounds a bit not clean.
is it possible to set this command "on connection" of the modem only?

I notice also that after reconnection & modeswitch command, I may need to manually disable/enable the interface to have the gateway online again...and there, I have no clue how I could make this automatic...?

[3kj2w]

Hi,
I made some experiments some time ago with this modem and because the problems you mention now I use a TL-MR3420 with this modem, and no more problems...

When I used only E3372 I made my script, I also added a cron that will run it every 5 min.

On my setup I first set ue0: static 192.168.10.10/24 gateway 192.168.10.1, add gateway... gateway group...
and pkg install usb_modeswitch

It is possible that you will need to make changes to this script for your setup but you have the main work done:

Code Select Expand

#!/bin/sh
# delete cd0 prepare USB E3372 modem
# LLC script v0.1

# test if USB dongle exist
usbdata=`usbconfig | grep HUAWEIMOBILE`
if [ -z "$usbdata" ]
then
echo "INSERT USB E3372 !"
exit
fi

cdata1=`/sbin/camcontrol devlist | grep cd0`
# test if no exist cd0 -> NO cd0
#echo "$cdata1"
if [ -n "$cdata1" ]
then
# exec commands to eject cd0 and activate network modem
echo "EJECT cd0"
/sbin/camcontrol eject cd0
/usr/local/sbin/usb_modeswitch --default-vendor 0x12d1 --default-product 0x1f01 -J
fi

#echo "EXIT USB-E3372 CD"
#exit 0

ue0inet=`/sbin/ifconfig ue0 | grep inet`
# test if exist ue0inet
while [ -z "$ue0inet" ]
do
echo "working to ue0 IP..."
/sbin/ifconfig ue0 up
/bin/sleep 1
/sbin/ifconfig ue0 inet 192.168.10.10 netmask 255.255.255.0
ue0inet=`/sbin/ifconfig ue0 | grep inet`
done

#/sbin/ifconfig ue0
echo "EXIT USB-E3372"
exit


[szty0pa]

Hello,

I have a very similar setup (DSL with USB LTE failover), but i am using an older android phone as the modem. My problem is exactly the same as yours: if/when the USB connection to the phone goes down (bad cable, phone rebooting, etc.) it brings the whole rig down. :( Kind of counterproductive if you added the failover for reliability in the first place. ;)
What I noticed that sometimes first the web UI freezes but SSH and network connectivity still works for a minute or two, other times the whole system freezes straight away and ping returns 'network unreachable'. This indicates some kind of overload to me.
As a first idea of remedy I removed the failover interface from NetFlow (so it is not used by any services, esp. not Suricata or Maltrail), which I hope will fix the freeze. I keep my fingers crossed, will report back if the phone should disconnect again. Hopefully this might help you as well.

[szty0pa]

...nope, sadly it didn't help. opnsense still freezes when the usb modem is disconnected. :(

[GiantJack]

Hi,
I made some experiments some time ago with this modem and because the problems you mention now I use a TL-MR3420 with this modem, and no more problems...

Hi!
do you use the TL-MR3420 "between" the huawei USB modem and Opnsense ?
If yes, I assume you have a dual NAT then ?
I do have a TL-MR3020, but I didn't wanted to add it in between to avoid this.

[GiantJack]

...nope, sadly it didn't help. opnsense still freezes when the usb modem is disconnected. :(

at least, I'm not alone :-)

[3kj2w]

Because in my case TL-MR3420 with 4G/LTE is used only for WAN backup and I can't have open ports on 4G/LTE or a true Public IP with my operator I have no problems with dual NAT, Primary WAN - fiber optic is not used via TL-MR3420.

[GiantJack]

Because in my case TL-MR3420 with 4G/LTE is used only for WAN backup and I can't have open ports on 4G/LTE or a true Public IP with my operator I have no problems with dual NAT, Primary WAN - fiber optic is not used via TL-MR3420.

Good point!
I will give a try with my MR3020.

[GiantJack]

Hi !

I would like to share that a 4G backup gateway works fine even with double NAT. (as long as you need only access to internet and no incoming port which is anyway not possible for most 4G connexions).

I use a MR3020 connected to opensense by ethernet and with my a 4G modem e3372 connected by USB.

Also no problem to access the web interface of the MR3020 and of the modem from my LAN in case I need to tune or check some settings.

Disconnecting the modem kills the gateway (of course), but does not crash opnsense like before !!

Exactly what I need :-)


I also tried to aggregate connexion (dsl + 4G) from my 2 gateways...it works more or less (sometime perfect, sometime not working). I'm not sure of the reason.
Anyway I use this only sporadically, for example if needed to download faster some large file (for exemple a PS4 game update).