Planning to recycle the old firebox we have at work, and was wondering if pFsense would do a feature based on what our web team want to do with their web servers.

Situation goes a little like this, and is something that worked with Smoothwall (although we never got the internet working due to limitations!):

Webserver runs on ip address 192.168.1.xx ports 80 and 443 and serves people, we use several ips for different websites.

We decide, oh we need to install a critical update on the live web server, so, we need a script that will then switch all nat entries it to our secondary server on 192.168.1.1xx. On smoothwall we had a process through ssh that would run a command to update the config with all nat internal ip's with a 1 in front of the last delimiter (i think it was an iptables command)

I had a look at the load balancer on my pfsense firebox at home but we don't share sessions across the two servers and the second one is purely a failover…