Want to connect to my own server, which is at my office, from anywhere
 

I have a server in my [home] office which runs a mysql database and keeps track of invoices in and out, partslists for my PCBs etc. I would like to be able to access this and enter purchase orders, check stock etc when I am out of office. The server is, of course, running Linux!

It is sitting behind a Vigor DSL modem/router/switch which has VPN capabilities. I have previously used it to connect to the server from a friend's place, but he also had an identical DSL modem. I would like to be able to do this from my Linux laptops when away in any place, wherever I get on line.

Also, I want be able use a different IP address (I have five with my ISP) to connect to the server than I have for getting on-line. I think it would be good to have two network cards in the server, one that only allows access to stuff from the outside world, one that allows me to get at the server when in the office. (Is that sensible?)

Would anyone be able to advise me on how to approach this please? Thanks!

There are several ways to make this work, and you can use a 2nd IP, but it will not really be any more secure.

I would look at port knocking, it is a way to tell the server that it is you.

The short answer is you hit a port that you previously assigned (use something high and random) this "knock" tells your server firewall to open port 3306 (mysql) to the IP that just knocked. Then you can connect to mysql from any remote port/location.

On your DSL device make sure you open the knock port and the mysql port to your linux box.

You run a compatible VPN client on your laptops, or run a VPN of your choice on the server and laptops.

+1 to VPN on server and laptops with port forwarding on the DSL modem/router/switch so your VPN client laptop on the big bad internet can reach the server on the office LAN. OpenVPN is relatively easy to set up.

Anybody who can log on to the laptop (anybody with physical access and the technical knowledge) would be able to access the server unless you add a password (either for encrypted file or file system on the laptop or for VPN authentication).