Layer 4 switching in FBSD?

[Steve Bertrand]

I'd like to implement some style of load balancing for my smtp and
spamassassin servers. It was suggested to me that layer-4 switching was
the way to go. I do not want to do round-robin DNS, as it could prove to
be a problem if one of the boxes goes down.

For bridging type firewalls and/or network surveylance equipment, I often
put 5 NIC's into a FBSD box and it works perfectly great.

I'd like to know if FBSD is capable of layer-4 switching, or some other
similar technology to load balance that it can do while loaded up with
NIC's.

Tks for any input, suggestions or advice.

Cheers,

Steve