*SOLVED* more than one connected device modem disconnect

[brcisna]

Hello All,
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*SOLVED*

the fix for this problem was to configure the lan interface ( to be natted to wwan0) manually, rather than using the NetworkManager gui. Not sure why this is as the routing tables looks identical.

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New to cellular setup for internet access.

Have a Debian Bullseye box setup as a router with a Sierra Wireless em7455.
The modem will stay connected forever without any problems , but randomly if another device connects to this router through ethernet or wifi the modem will start resetting. Once the modem starts doing this resetting thing the only fix is disconnect the second connected device. Once the device is disconnected the modem straightens out immediately and server/router has internet again. Am very familiar with dnsmasq which is what is running on the Debian server but not sure what is causing this. In syslog of course NetworkManager is constantly showing modem disconnecting, reconnecting. Signal strength is about -75 dBm.
Using the in kernel libqmi & libmbim packages for connection interface
Almost certain i need another setting in dnsmasq to do with IPV6 . Wireshark shows on the wwan interface, constantly "Leaving group, rejoing group when it does this resetting thing. Seems also possible Visible sees more than one connected device it may auto disconnect.

Thank You

[Dr-BroadBand]

What version of Debian Bullseye

10 or 11??

A wireshark user wow! Impressive

Have you tried to stress test your LAN of your router with Iperf3?

[brcisna]

hello Dr-BroadBand

thanks for the suggestions.

This is Debian 11 ,,10 would have been Buster
yes very impressive wireshark nerd

I did try the iperf stress test lan and out to remote server public,,and no dropped packets
This box is setup as an ltsp server so not knowing what this is thin clients can pxe boot from it as a dumb client. We have used this for 15 years for the crumb crunchers to hack around on.

The modem will never do the resetting thing sitting at the console of the server you can web browse all day long. The problem occurs when a client machine starts web browsing. It may be fine for an hour and sometimes as little as 15 minutes.
The key is if the modem starts resetting on server, as soon as the client is shut off the modem stays online again at the server instantly. The indicator in menu bar stops spinning reconnecting. Web browsing happens again(on server/router) .
Never see anything obvious in dmesg when this happens.

This is the pic-e adapter am using not that it makes any difference. I did remake the usb header wire setup with 20 gauge wire for power supply to the modem just to maybe circumvent this snafoo but still remains the same.

Code: Select all

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Using the latest,greatest Sierra Wireless firmware on modem,not sure of number.
this is inside a brand new Dell Optiplex machine and have noticed an oddity in that with the modem in this machine when rebooting the interfaces will enumerate to increment up or down one number from time to time.In other words enp2s0 becomes enp3s0 and same way with wireless interface. With the modem out of the pci-e slot this never happens.
Sorry for long post.

Thanks again

[brcisna]

Hello All,

Sorry,,,for answering my own question here. Just hoping this may give someone else some answers.

After putting my sim back in my phone received from Visible a couple months ago,,,which i only used a couple days,,at the time. I noticed setting up tether it does only allow for one tethered device,,then of course the phone does not have internet access.
This is exaclty what I am experiencing and dnsmasq will not work around this.
For example can web browse all day with the server the modem is in,and connect an android phone to the wifi interface of the server and connect a thin client to the ethernet of the server. In just a short amount of time,web browsing from either one of the connected devices the modem starts resetting thing.
All along i thought i had something wrong with the modem.

Thanks

[mtl26637]

Don't think you are being ignored here, just that most here are using wifix/goldenorb setups or routers and do not use a setup such as yours. Sounds like your setup is based more along the lines of a single client system? If I was to guess it sounds like your setup is passing all clients directly to the provider and the provider is seeing multiple connections for a single sim setup. Most setups here set behind NAT system or router where single connection to a provider and multiple connections to router or device on the other side. I could be way off but from your last post it kinda fits no?

[LoveMeSomeCALTE]

The primary question that I have is what setup that Debian Bullseye box setup as a router is using.

Are the scripts/etc for that setup on a github somewhere - otherwise it's very difficult to know what we are even working with - leave alone, help debug

[brcisna]

Hello,

Thank you for the feedback.

Have what I think are the correct rules for doing NAT Masquerade in the iptables for both IPV4 & IPV6

-t nat -A POSTROUTING -o wwan0 -j MASQUERADE
A INPUT -i wwan0 -m state --state NEW,INVALID -j DROP
-A FORWARD -i wwan0 -m state --state NEW,INVALID -j DROP

in sysctl have the following:

ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1

For some reason ,think am missing something in IPV6 though.
Have messed around quite a bit with settings in dnsmasq as well, but still seems like multiple connections are being detected by carrier, which i never even thought would be a factor ,,of course ,,until getting into this.

Thanks

[LoveMeSomeCALTE]

Without looking at the exact commands that were used, it continues to be hard to even guess what's going on.

The simplest solution is to put a GO router with the modem in front of this box and see if you can reproduce the issue.