NethServer 6

An iOS can't access to cardDAV service.
From SOGo official documentation:

Since Mac OS X 10.6 (Snow Leopard), Apple AddressBook can be configured to use SOGo.
In order to make this work, you must add a new virtual host in your Apache configuration file to 
listen on port 8800 and handle requests coming from iOS devices

This is not true. The client can be configured to use the standard 443 port with a different URL like http://server-name/card.
In the client configuration set Server as "http://server-name/card".

Patch for httpd configuration:

--- /etc/e-smith/templates/httpd/vhost-default/30SOGo    2013-04-15 16:51:25.000000000 +0200
+++ /etc/e-smith/templates-custom/httpd/vhost-default/30SOGo    2013-04-24 15:13:26.532354215 +0200
@@ -69,7 +69,12 @@
 #   Allow from your-cas-host-addr
 # </Proxy>

-ProxyPass /SOGo http://127.0.0.1:20000/SOGo retry=0
+ProxyPassInterpolateEnv On
+ProxyPass /SOGo http://127.0.0.1:20000/SOGo interpolate
+ProxyPass /card/SOGo http://127.0.0.1:20000/SOGo interpolate
+ProxyPass /card/principals http://127.0.0.1:20000/SOGo/dav/ interpolate
+ProxyPass /card/ http://127.0.0.1:20000/SOGo/dav/ interpolate
+

 <Proxy http://127.0.0.1:20000/SOGo>
 ## adjust the following to your configuration