Hi We are moving our small office a few hundred yards to a new building, and as our telephone provider cannot hook up the adsl line in time, we have to temporarily rely on a 3g router (Teltonika RUT104 (HSUPA router) or accessing the internet. The router simply has a sim card inserted (that has a static IP), and can be connect to a switch for other users to have an internet connection. My question is: As our existing ADSL router (Draytek Vigor 2820) has a SPI firewall for protection, if we are to just use the 3g router in place of our regular router, then we wouldn't have the same protection from attack with the 3g's standard firewall. (Our server is protected by the hardware firewall built in to the router). So can we connect the 3G router to our existing router, so that we benefit from the firewall protection, and also make use of the 3g internet connection? I presume we just connect the 3G router to the existing router (DHCP supplied by the server), but unsure what changes we should make to either router for them to work together. It's basically the uncertainty of the 3g's firewall protection, which got me asking the question. I hope this makes sense!! Any help would be appreciated.