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> Sound OK so far? |
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Yup, same setup I'm using (kinda). Works out very well. |
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> Next steps I think are figuring out how to provide DHCP |
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> to both internal subnets from the same Gentoo box, and |
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> what gateway address(es) the clients should use. |
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The gentoo box is the gateway. Assuming it is 192.168.{0,1}.1, |
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that would be the address to feed to the internal network boxen. |
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DHCP is easily configured to serve based upon the card, you just |
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need to dig into the config file to get it set up. Don't forget |
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to add iptables rules to block DHCP traffic coming or going on |
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the card connected to the network; you don't want to offer DHCP |
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to anyone outside of your internal network. |
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Along with DHCP you might want to add a caching DNS proxy on the |
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gateway box. This will simplify the network settings of the |
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internal systems (everything network-related would point to the |
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gateway). |
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> Finally, I need to be able to do port-forwarding from the |
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> outside to a specific host on one of the internal subnets. |
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> Can I do that? |
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Yes, it's all done via iptables. You'll need to chain it up; the |
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cable modem forwards to the firewall which forwards to the gentoo |
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box which forwards to the specific host. You'll have to get all |
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of the DNAT stuff right along the way. |
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> One quandary I have is regarding the hardware firewall. We have |
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> money invested in it, but does it buy me anything now that we are |
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> creating the 2 separate subnets? Should I just sell it and let |
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> the Gentoo box be the firewall as well? |
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As one poster said it will offer another layer of protection, but... |
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Personally I found it unwieldy to maintain iptables rules in such a |
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fashion. If traffic can't get to/from a destination you'll have like |
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5 points of failure: the local box, the switch, the gentoo box, the |
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firewall, and finally the cable modem. |
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And with the correct iptables rules in place your gentoo box will |
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be just as secure as the firewall appliance. It also offers you the |
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opportunity to see all incoming traffic, not just the traffic the |
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firewall appliance allows. So, for example, I have the ssh port open |
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on the gentoo box but it is basically a honey pot; folks trying to |
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connect there get automatically added to the blacklist and traffic |
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is blocked from them permanently. |
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I'm not sure how feature-full your firewall appliance is, but the ones |
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that I was using had limited port forwarding capabilities (10 to be |
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exact). Once I wanted to start hosting basic services, I quickly |
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consumed those ports (imap, pop3, ssh, ident, smtp, ftp, http/s, ...). |
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This however might not be a problem for you. |
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-- |
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