[horde] Horde stops working if firewall blocks external domain

[Louis-Philippe Allard]

Hello list,

I have a Horde Webmail 5.2.17 up to date running on a Centos 7 VPS.   
MySQL database is hosted on another VPS ont he same LAN.   
Communication between VPS'es is 100% functional without any issues.

Once in a while I login to Horde which uses IMP as my auth  
application. IMP uses my Gmail account to authenticate me to Horde.   
All has been working well until I made some changes to my firewall and  
added the domain "ssl.google-analytics.com" to a block list (it is  
part of an automated blocklist feed from iblocklist.com).

What happens is that I am working in Horde (calendar, emails, tasks,  
etc) then all of a sudden, connectivity stops, the apps are not  
responding, and I see the red popup at the bottom corner of the screen  
saying "Error communicating with server".

I have successfully connected this type of incident with the firewall  
logs and indeed it is when "ssl.google-analytics.com" is blocked.

My question is: why is horde insisting to connect to an outside domain  
(google's in this case) when it is not necessary?  All data is stored  
in a local LAN database, and the VPS is also on LAN.  Actually, I  
would expect only IMP and the emails to cease working if it  
***really*** needs to use "ssl.google-analytics.com" to function...

That looks sketchy to me...

Anybody can shed some light on this?

Thanks!
  Louis-Philippe Allard
lp.allard.1 at gmail.com
Sent using Horde Groupware on GNU/Linux