Please advise:
Network settings enables the same hardware device to be configured in different ways, so for instance I can apparently set it to detect network settings automatically (so it takes the settings from the ISP's server using DHCP, just as I already do now) and also manually set it to a local address (say for instance 10.0.0.1, 127.0.0.1 or 192.168.0.1). These can be identified as eth0 and eth1, both referring to the same network card.
My questions are based on: if both settings are activated simultaneously, can I use this feature to connect to the Net on one and connect to a local network with the other?
If the machine is connected to the Net using a hub, can I then use the machine to act as a local mail server (ie, pick up my mail from my various POP addresses and hold them for local distribution when the other local machine(s) are switched on)? I presume such mail servers (qmail, etc) can also be configured to trash spam and viruses, just as clients do. And what about browsing?
Is this what is meant by proxy? Can the box also act as a firewall and virus trap for browsing, using a suitable app?
Guidance much appreciated.