I was hoping I could use some expert help on my ppp interfaces.

My setup is as follows. I have a Rpi 3 Model B that has two ppp connections (one 2G sim900 module and one 3G huawei dongle).

My system is segregated in such a way that some specific traffic needs to go through one modem and others on the other (data cap limitations).

I have setup routing tables using iproute2 and can confidently use the appropriate commands to set up the routing as required (in more detail, ppp1 is required to handle a set of source addresses while ppp0 services the other).

My specific problem is with the interface names. On bootup, my sim900 module sets up a ppp0 interface without issue (which is mandatory). However, when I connect my 3G huawei dongle using the sakis3g script, it disconnects my current ppp0 interface and takes it over invalidating my ip routes. (gsm module comes up later but connected to ppp1 now)

It is mandatory that my gsm module connect on ppp0 and 3g dongle connect on ppp1, even if one or the other goes down. Can someone please help me put this right?

Thank You


auto lo
iface lo inet loopback
iface eth0 inet manual
allow-hotplug wlan0 here
auto ppp0
iface ppp0 inet ppp
provider sim900

How have you get your connection with your sim module using ppp? I am trying with ppp and chat, but I think i have problems to authenticate, but I do not know how to do it, and when i do sudo pon myfile, I get an error in connection.

Thanks in advance!!

  • You better open up a new question since debugging requires more information and error logs. As an initial checklist, see whether your APN parameters are set properly in the chatsctipt and baud rate in the pppd peers file as well. Refer this wiki.archlinux.org/index.php/3G_and_GPRS_modems_with_pppd for setting up a 3G/gprs connection – user3889963 Oct 8 '17 at 8:24

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