Problems configuring gateway/firewall with static IP addresses - RESOLVED

[Matt Singerman]

Hi all,

After sending my last email, I realized I was doing everything 
completely incorrectly and reconfigured the machine to act as a network 
bridge.  It took me about 20 minutes to set up and is working 
flawlessly.  Thanks for your help!

Matt Singerman wrote:
> Hi Ed,
>
> Wow...  This all seems, uh, complicated.  Maybe I am going about this 
> in the wrong way?  Our existing gateway machine definitely doesn't 
> have a configuration this complex, especially since I don't have any 
> control over 141.161.185.38.  What would be the best method to 
> firewall off just one part of a network - to have just a few servers 
> on 141.161.111.x behind a firewall, and all the other machines on that 
> same network not behind it?  Am I making things too complicated here?
>
> Ed Greshko wrote:
>> Ed Greshko wrote:
>>  
>>> I wrote....
>>>
>>>    
>>>> 1.  Assuming eth0 is the Internet facing interface you need to change
>>>> its IP address as well as its netmask.
>>>>
>>>> IPADDR=141.161.111.1
>>>> NETMASK=255.255.255.252
>>>> BROADCAST=141.161.111.3
>>>>       
>>> That was only an example.  The important thing is that the netmask 
>>> needs
>>> to be 255.255.255.252 which gives you only 4 IP address on that
>>> interface and of these only 2 are usable as the others are the network
>>> address and the broadcast address.
>>>
>>> You could have...
>>> IPADDR=141.161.111.242  for eth0
>>> IPADDR=141.161.111.241  for 141.161.185.38 interface
>>> Broadcast=141.161.111.243
>>> Network=141.161.111.240
>>>     
>>
>> Forgot to mention that in this case eth1 needs to be changed as well as
>> default gateways...but I think that was obvious.  However, I forget that
>> what is obvious to me may not be obvious to others so it is better to
>> mention it....even if it is an afterthought and increases traffic.  :-)
>>
>>
>>   
>