Re: Verizon Cellular service and NetworkManager shared networking

[Dan Williams <dcbw redhat com>]

On Sat, 2010-12-18 at 15:58 -0500, Andy Graybeal wrote:
> Hi everyone,
> I've purchased the Verizon Cellular internet service for home. I love
> it, especially when compared to regular dial-up, which is what I'm used to.
> 
> I have the USB760 and I got this to work just perfect after I followed
> the second post on this forum thread:
> http://ubuntuforums.org/showthread.php?t=1002262
> 
> One problem that I have is when I share the internet (USB760 = ppp0)
> over ethernet (eth0) with NetworkManager.. Verizon will disconnect...
> say every 20 minutes or so; sometimes 5 seconds, sometimes 45 minutes,
> but mostly around 20 minutes.
> 
> The service is disconnected by this: LCP terminated by peer a command
> sent from Verizon after what I've suspect (and from what I've read in
> the forums) they've received too many(?) private ip addresses sent to
> their public network. (here's the post confirming this:
> http://www.mail-archive.com/networkmanager-list gnome org/msg10840.html )
> 
> Here's a post with what might be the answer:
> http://www.mail-archive.com/networkmanager-list gnome org/msg14760.html
> The poster outlines changing:
> 
> iptables -A FORWARD -i eth0 -o ppp0 -j ACCEPT
> 
> to this:
> 
> iptables -A FORWARD -i eth0 -o ppp0 -m state --state
> NEW,ESTABLISHED,RELATED -j ACCEPT
> iptables -A FORWARD -j drop-and-log-it
> 
> 
> But how do I configure NetworkManager's iptable settings to get this to
> work? Is it in the NetworkManager's script files
> (none of which I
> understand)?
> 
> I don't understand iptables either. I'm a little better at pf.
> 
> Any help is appreciated.  I posted this to the ubuntu users list, but I 
> didn't receive any responses.

One thing you can do, for the time being, is make a 'dispatcher' script
that does this.  It's a small script that gets called whenever things
happen with the network, and in your case that's a great place to put
this.  The script gets called with the interface name that came up or
down, so you can just pop this command into a small script
in /etc/NetworkManager/dispatcher.d, and match against the interface
name starting with "ppp".  Note you'll want the IP_IFACE environment
variable from the script, not the actual interface name passed as a
command-line parameter to the script as $1.  Note that it won't *always*
be ppp0.  There's various information out there on creating dispatcher
scripts, and there may even be some already installed on your system.

Dan