Exchange original source IP address

RouterOS General
1

I have an Exchange 2010 server behind the mikrotik. I have set the zen spamhaus but it isn’t working properly.
When viewing the exchange smtp logs the source IP of the sender is always the external IP of the mikrotik.

Here is my nat config:
add action=dst-nat chain=dstnat dst-address=WAN-IP-MIKROTIK dst-port=25 protocol=tcp to-addresses=LOCAL-IP-SERVEREXCH to-ports=25
add action=src-nat chain=srcnat to-addresses=WAN-IP-MIKROTIK

Can the Mikrotik be configured to port forward without changing the original source IP address?

2

In the second rule you replace all source IPs absolutely for all packets.
Try to limit this rule just for packets going to exchange IP or just remove this rule. The first one substitutes WAN IP with local without changeing src IP.

The problem is that if you connect to WAN IP from LAN then you need HarpIn … look here for longer explanation: http://forum.mikrotik.com/t/port-forwarding-problem/93224/14