I recently tried to use a Raspberry Pi Model B+ as a gateway between the internet and some equipment. The idea was to have a 3G modem (Huawei E3531) connected to the internet, which works fine, and route the connection to my local network. On my local network I have a webserver, which I need to access from the internet, and therefore I need the 3G modem to allow INBOUND traffic. I have a SIM card with static IP address, so it is not a ISP problem.
But I found that the Huawei E3531 3G modem does not allow INBOUND traffic, and when I started to google the subject, it seems hard to find a 3G modem that allows inbound traffic.
EDIT: I used the term INBOUND out of context, by INBOUND I mean that you from the internet connect to the webserver on the static IP.
Which modem to select? Or is there any other clever way to do this ?