[NTLUG:Discuss] routing concept

[Richard]

Leroy Tennison wrote:
>
> Terry has alluded to an issue I was going to raise, are the /29 (inside 
> network) registered Internet addresses or are they something someone 
> just picked?  
Yes, the ISP is routing a real world /29 subnet to the IP address 
assigned to eth0.   How I handle SNATing on that box is what is getting 
my panties in a wad.  I don't want to SNAT the IP address bound to 
eth0.  I want to SNAT the IP addresses on the /29 subnet 
......only.....I'm having a bear of a time understanding the routing 
decisions the kernel makes when dealing with monitoring one interface 
when the routing is going out the other interface....

I wonder if INTERFACE is the key word here....

If the dead-gateway patches mark the interface as OFFLINE.......and the 
/29 real world subnet ip addresses are bound to the same 
interface....then..  MAYBE...just maybe the two networks on one card 
will be considered on the same interface.
> The reason I ask is that, unless they are 
> Internet-registered addresses, you are going to need to do Network 
> Address Translation (NAT).  If I understand you correctly your 
> Internet-facing host has only one IP address facing the Internet. 
There are TWO external (PUBLIC IP) paths to two different ISPs and three 
internal (PRIVATE) networks each of which has one or more SNAT address set.

I should do a dia diagram......

-- 
Richard