ipchains, NAT, multiple uplinks

Hi,
I'm beginning to convert my Linux firewall to use multiple uplinks to
different ISPs.
There is one thing that I don't understand how do to (even before
attempting to do anything): right now I have an ipchains rule which
set the source address of all packets going to port 25 to a specific
ip address which has a reverse DNS record which is pretty much
required for SMTP connections nowadays. What should I do with that
rule now that the connection might actually be going through another
uplink?

Thanks!

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>>>>> meshko writes:
meshko> Hi,
meshko> I'm beginning to convert my Linux firewall to use multiple uplinks to
meshko> different ISPs.
meshko> There is one thing that I don't understand how do to (even before
meshko> attempting to do anything): right now I have an ipchains rule which
meshko> set the source address of all packets going to port 25 to a specific
meshko> ip address which has a reverse DNS record which is pretty much
meshko> required for SMTP connections nowadays. What should I do with that
meshko> rule now that the connection might actually be going through another
meshko> uplink?

Since, your IP (which has reverse DNS record setup) can't be used as
source address in IP packets going out via another link, so you need to
relay all your IP packets destined on port 25 via previous link. OR
setup reverse DNS records for IP address on another link.

meshko> Thanks!

HTH
- --
Ashish Shukla आशीष श�क�ल http://wahjava.wordpress.com/
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On Jan 18, 9:26 pm, mes...@gmail.com wrote:
> Hi,
> I'm beginning to convert my Linux firewall to use multiple uplinks to
> different ISPs.
> There is one thing that I don't understand how do to (even before
> attempting to do anything): right now I have an ipchains rule which
> set the source address of all packets going to port 25 to a specific
> ip address which has a reverse DNS record which is pretty much
> required for SMTP connections nowadays. What should I do with that
> rule now that the connection might actually be going through another
> uplink?
>
> Thanks!

I think you will have to do alot of work so you get all what you want
to do to be active, This may help you,
http://www.lartc.org