[CentOS] Attaching LinkSys WRT54GL to CentOS machine

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