ok, got it, at least with internet explorer it works fine, Chrome needs extra info in the certificate.
here is how i did it :
first of all, you need to know your dga4130 hostname, by default if you didn't change it, it should be
modemtim, so check if you can do a
ping modemtim to verify. if you have a particular configuration then just configure your dns to point to your modem IP when using the domain name "modemtim". you can also edit your HOST file in your PC.
Now from putty with opkg, you have to install
openssl, i think it was installed on my modem with the Ansuel GUI.
once installed, type this :
openssl req -x509 -nodes -days 3650 -newkey rsa:2048 -keyout nginx-selfsigned.key -out nginx-selfsigned.crt -subj '/CN=modemtim'
this will generate the 2 files :
nginx-selfsigned.key
nginx-selfsigned.crt
move then in the /etc/nginx/ folder
now edit nginx.conf and add the new values in bold :
sessioncontrol.setManagerForPort("default", "443")
ssl_certificate /etc/nginx/nginx-selfsigned.crt;
ssl_certificate_key /etc/nginx/nginx-selfsigned.key;
once done, restart nginx. /etc/init.d/nginx restart
now you have to start Internet explorer as
administrator, this is important.
once done go to
https://modemtimnow it is too long to give details... but what you have to do is to display the certificate details by clicking the "padlock" in internet explorer, then click to install the certificate, choose to add it in the TRUSTED ROOT CERTIFICATE AUTHORITY. Once done close internet explorer and open it normaly, go to
https://modemtim and now there is no errors.
Now if you watch your certificate, it should look like this :