John R Pierce wrote:
On 04/24/11 11:15 AM, Timothy Murphy wrote:
Without any information on what the purpose of such a setup would be, it's close to impossible to give you any recommendations. Is it because you want to use your CentOS system as a firewall? a router? a HTTP proxy? a network sniffer?
I don't actually think my motives are relevant. In case I didn't described the situation clearly, my CentOS server is connected to an ADSL modem by ethernet (eth0). The modem's IP address is 192.168.1.254 .
your goal is very relevant if youj are expecting us to suggest a workable solution.
but ouch, sounds like your modem is ALSO a NAT router, and is probably running DHCP already. what IP is eth0 of this linux PC ?
you want to avoid 'double nat' where there's multiple layers of address translation as its just ugly as heck to troubleshoot, and adds complexity without any additional value..
assuming I'm right, and your modem is in fact doing NAT routing too, then I'd put DD-WRT or Tomato opensource firmware on the WRT54GL, configure it for LAN only use, so all 5 ports are LAN, plug it into the modem, plug your computer(s) into the WRT's switch also, and configure the WRT"s wireless. now all your systems will be on that 192.168.1.xxx subnet.
He wants to pass all traffic through CentOS box so he can monitor traffic, run bandwidth shaping, etc..
As for double-NAT, it's not so horrible. I now people using even triple-NAT without issues. Not recommended, but much easier for noob's then learning how to route properly. 7 years of experience speaking.
Ljubomir