Two Companies One Internet

[Kevin253]

I have a customer that has two companies within his building. He has one incoming internet connection that he wants to share between the two companies. The companies need to be on two seperate secure networks yet share the same interent. One of the companies wants to set up a Branch offie VPN back to their headoffice.

Do I need two static IP's for these, or how am I best to set this up? Will a simple router allow the VPN traffic for VoIP phone pass through it to the one company and not to the other?

Any help is appreciaed very much.

 

[biv343]

Two static IPs would be best. Give them each their own firewall to the internet that they can do with what they want.

 

[Kevin253]

Can I still give each of them their own firewall with one IP?

Would I put the DSL modem into a hub, then go from a port on the hub to a port on each firewall?

 

[biv343]

If you only have one IP then you can only have one firewall. Two separate devices can't share the same address.

You could run them off the same firewall - just pay attention to your access lists so users on subnet A can't get to resources on subnet B.

 

[anthonyanderberg]

The problem with only having one IP address is that it only gives one entry point for incoming services like VPN, web servers and such. With only one address you have to firewall incoming services by protocol/port number, which may be a pain down the road. Depending on what kind of connection you have adding a second IP address some day might require "giving back" the first address and getting a block of 2-4 new addresses routed to your location, which could also be a pain.

In the end you'll have to check with the ISP and weigh all these potential pains with the known pain of extra cost for a second IP address.