Linux pc as a router or firewall

[techtata]

Hi,In a Linux network one Linux pc/computer can be used as a router and/or firewall. If this is the case then one does not need to buy the actual router, which it is not a computer itself. Nor is there any need to buy the expensive hardware firewall. Is firewall only software or it can be a hardware as well? Is this true? I have some confusion here, so please help me clarify a few things. As far as I know both router and firewall are not computers themselves but another type of hardware. I have seen them in real life. But do not know much about them. Linux OS offers certain applications that can be set up in such a way that a fully functional Linux pc can behave like a router and/or firewall without actully needing one. This is all I understand. Thanks

 

[vishalrao]

Have you tried googling/looking up wikipedia?Equipment like firewalls/routers can be custom made like those big brands Cisco, Juniper etc, these are "specialised" computer designs with their own chips/memory arrangments and yes they do run operating systems with software based (possibly firmware and FPGA based) code to perform the firewall/routing operations.Even your/my simple DSL modem+router has all the firewall/NAT/DNS capabilities (not router though!)...And yes, you can build your very own Firewall, Router, DNS server (like you know about web servers), using cheap PC components (low power CPU, HDD, RAM) - you just need DUAL (two) NICs (network cards) - one is connected to the outside world (your ISP) and the other is connected to your internal LAN through switch/hub where the other normal computers can sit and collect IP addresses through your DNS server, surf web via your web caching proxy and all the while be protected by firewall/NAT rules (edit: this is mostly my layman understanding of this stuff)

 

[techtata]

yes they do run operating systems with software based (possibly firmware and FPGA based) code to perform the firewall/routing operations.

Hi VishalRao,

Thanks for the quick reply, I know that big vendors like Dell, HP etc. selling firewall hardware, but never had any idea about their software components, let alone operating systems. I am happy that you have clarified to me that these hardware firewalls also have an operating system.

Thanks and please feel free to add anything that is useful and basic to the idea,

---------- Post added at 04:51 PM ---------- Previous post was at 04:06 PM ----------

I just found this on Cisco site, I think it is a hardware firewall comparison chart, not sure...

Cisco ASA 5500 Series Adaptive Security Appliances Models Comparison - Cisco Systems