Enabling Connectivity Checking in NetworkManager

[Scott Kitterman]

On Tuesday, July 10, 2012 02:41:35 PM Mathieu Trudel-Lapierre wrote:
> Hi,
> 
> At UDS some of us discussed the connectivity checking feature of
> NetworkManager, which landed not long before the Precise release.
> 
> Connectivity checking would be a big benefit in helping with properly
> recognizing the cases where you're connected to wireless, but actually
> behind a captive portal which catches and redirects requests --
> sometimes not all that gracefully. The most frequent impact of this is
> a corrupted apt cache when the files don't fail to be downloaded, but
> instead contain http data from the captive portal.
> 
> I'd like to enable connectivity checking in NetworkManager. We'd use
> http://start.ubuntu.com/connectivity-check.html, running the check
> every 5 minutes starting from the connection being established.
> start.ubuntu.com has already been in use for a while to verify
> connectivity from the installer, IIRC.
> 
> The net impact of this change will be a slight modification in the
> actual status reported by NM -- NM_STATE_CONNECTED_SITE, rather than
> NM_STATE_CONNECTED_GLOBAL. Most applications that depend on
> NetworkManager to check connectivity already handle (the old state
> NM_STATE_CONNECTED which now maps to GLOBAL), CONNECTED_LOCAL,
> CONNECTED_SITE and CONNECTED_GLOBAL as meaning that they have internet
> connectivity, so I don't expect consequences for the vast majority of
> applications.
> 
> As for the actual change, it is limited to the
> /etc/NetworkManager/NetworkManager.conf file; to which the following
> will be added:
> 
> [connectivity]
> uri=http://start.ubuntu.com/connectivity-check.html
> response=Lorem ipsum
> 
> See the manual page for NetworkManager.conf(5) for the details of what
> these settings do.
> 
> Please let me know if you have questions or think there are good
> reasons not to enable this feature. If there is no response by the end
> of the week, I'd like to proceed with a enabling this in Quantal and
> making sure it gets well tested.

I think that a significant fraction of Ubuntu's user base is (reasonably) very 
sensitive about privacy issues.  While this is no worse the the NTP check that 
already exists (that is controversial), I don't think it  should be enabled by 
default.

Scott K