Re: Mobile Broadband - disconnect after 2 mins.

[Dan Williams <dcbw redhat com>]

On Thu, 2008-10-23 at 00:17 +0100, Rick Jones wrote:
> --On Wednesday, October 22, 2008 13:48:21 -0700 Gilbert Mendoza
> <gmendoza gmail com> wrote:
> The CDMA connection does not have the "Send ppp echo
> ¦ packets" checked... which was explained to me as LCP echo.
> ¦ 
> ¦ In the bug report, I also noted a work around, which is to disable
> LCP
> ¦ echo requests and interval setting in the global PPP options file:
> ¦ 
> ¦ /etc/ppp/options:
> ¦ 
> ¦ lcp-echo-interval 0
> ¦ lcp-echo-failure 0

So the pppd defaults appear to be to ignore LCP echos.  If the box in
the connection editor is unchecked, NM will _not_ send lcp-echo-interval
or lcp-echo-failure to pppd.

However, if those options were specified in /etc/ppp/options at all, it
appears that pppd will read that file no matter what, and thus you'll
get lcp echos turned on even if NM didn't tell pppd to turn them on.

I will modify NetworkManager to always pass lcp-echo-interval and
lcp-echo-failure as "0" whenever the box is unchecked in the connection
editor, to ensure that /etc/ppp/options gets overridden, and that people
don't get whiplash from stupid pppd config hierarchy...

> Yes, well spotted! Thanks, I'd forgotten about default ppp options,
> that tweak works for me too. So the problem is 2-fold:
> 
> 1. The "PPP echo" option in the UI is not implemented, and stays off.

But that should mean that lcp-echo-* aren't passed at all, which is fine
because most people don't want LCP echo packets.

> 2. Nothing overrides the default PPP (LCP) echo options, so even
> though the UI says off, if the default is on, echos are still sent.

And this is of course the real issue.  Thanks pppd!

Dan