I need to load balance SMTP to handle some applications that don't know how to use MX records.
I set up a Netscaler using the TCP option on port 25 and now Exchange sees the source IP as that of the DMZ of the Netscaler for every connection, not the client.
Obviously this prevents RBLs, Whitelists, and all other IP-based reputation to fail. It also make it impossible to whitelist a trusted IP for anonymous relay.
How should I configure the NetScaler (or Windows Load Balancing) so that I can allow load balancing yet still maintain visibility of the source IP?