Question : Creating several VLANs on a switch to share a common Internet connection.

I've been trying to create the following for a client.

I have a Linksys SRW224G switch on which I want to create several VLANs both to improve network performance and for security reasons. These VLANs need to share a common resource being an Astaro Security Gateway firewall/UTM device.

To cover the hardware the Astaro system is built on a Dell GX240 box with a 3Com 3C905 NIC which is supposed to handle 802.1q traffic. Additionally the Astaro system is running the most current version being 6.301. I configured the Astaro interface for as an ethernet VLAN interface as per the user's manual for version 6.

Note I'm still learning the ins and outs of networking (working on the CCNA currently) so hopefully I'm not missing the obvious here.

Questions:

1. Can VLANs be set to share a common port that connects to a common resource such as the Astaro Gateway? According to what I've read and the tech people at Linksys the answer is yes however three different attempts to get a solution from them didn't work. Note I'm not trying to route between the VLANs just share a common gateway.

2. If yes what is the basic configuration to do so. i.e., how is the common port configured etc. A Cisco based explanation is fine as I'm more interested in understanding the concept.

Answer : Creating several VLANs on a switch to share a common Internet connection.

On a Cisco it would be like this:
interface vlan 1
 ip address 171.197.155.x 255.255.255.0 <---or whatever your subnet range is
 ip helper-address 171.197.155.4

interface vlan 2
 ip address 171.197.154.4 255.255.255.0
 ip helper-address 171.197.155.4