Bug 384929

Summary: Detect captive portals
Product: [Frameworks and Libraries] Akonadi Reporter: sedrubal <kde>
Component: DAV ResourceAssignee: kdepim bugs <kdepim-bugs>
Status: CONFIRMED ---    
Severity: normal CC: dvratil
Priority: NOR    
Version: 5.5.1   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Attachments: The certificate warning

Description sedrubal 2017-09-21 12:40:36 UTC
Created attachment 107933 [details]
The certificate warning

Akonadi should not try to sync with external servers (in my case the DAV resource) when the device is connected to a captive portal. If you configured to use a TLS secured connection, you'll receive many (!) certificate warnings if the captive portal web site is also available on a TLS connection and if your requests will be redirected to the captive portal website.

Maybe you can use NetworkManager to determine if you are in an captive portal:
$ nmcli networking connectivity check
Comment 1 Daniel Vrátil 2018-08-27 23:00:07 UTC
We tried using NetworkManager to detect whether we are behind a captive protal, unfortunately it sometimes had false positives. 

Maybe things have improved since then.