RE: Load Balance with health checks software?]

> Just looking at a "software" option to having a L4
load-balancer/health
> check router/switch and exploring the possibility of ipfilter.

What you're suggesting requires some of the same things I'd like to
use for butler, my secret-knock program. Namely, a ipf/ipnat API that
contains the rule parser and code to manage dynamic rules. As it is,
I'm going to get butler to call a preprocessor and then run ipf. I
suppose that the ipf command line forms a type of API, but it isn't
as powerful as I'd like.

An API would also support the construction of a rule-management user
interface, perhaps remote, which would be a good thing.

> You can also add and remove ipnat rules dynamically by using (-r). I
am
> unsure if it can be done without losing current sessions?

I believe it can if you don't use -F (for flush).

> Has this already been done?

I'm not familiar with the work that's happening in the Linux world, but
I
do know that there's been a lot of work on iptables & ipchains, so
perhaps
they would be alternatives for you.

> I would imagine I could potentially also add rules to "log" any RST

Meaning that the service has gone down but not the computer.
That would be useful.

Clifford Heath.