I have never done any real networking job but is presented with this task, would like some help/guidance in this, thx
Looking to establish a network of 30 computers, with a mail server.
Our current setup is ISP ----> Router ----> Network
we can have 5 static ips but it's currently set at dynamic to allow all 30 computers to be online at the same time.
The problem come with the mail server which require a static IP, and the ISP told us that if we were to set 1 static ip then the whole dynamic setting will be taken out and only 5 computers in the organization can go online at a time unless we buy more ip address. It's a all or nothing situation. Which is something we are not looking forward to do.
And of course, security is an issue too, since the ISP don't do port mapping, the ISP told us the only way to receive mail from the internet is for them to open up everything on the router for a particular IP address that the mail server will be setup at. The mail server will have no firewall protection from the router that way.
So i was thinking of making a proxy server with one of the computers, the setup i was thinking is:
ISP ---> Router ---> (spit):
1st IP address : Proxy Machine ----> Network
2nd IP : Firewall ----> Mail server
3-5th IP : future expantion
The Proxy machine will be protect by the router's firewall,.
The Mail server will be protected by additional firewall machine i will set up.
All computers run in MS enviroment, except the mailserver which is on Linux. Firewall haven't been decided yet.
Will this setup work? or can anything be modified to make it more efficient?
What firewall should I use? preferably free, stable and can be installed on a lower end machine.
Thx in advance for your help.