RBL- SMTP - IP Address Changing

RouterOS General
1

Hi,

I have an instance where incoming connections on our public interface to mikrotik, gets NAT’ed to our private machine on our network.

When the IP of our source server, for example: 196.0.0.1 hits mikrotik, mikrotik’s internal IP is for example 172.0.0.1; Mikrotik routes connection to the internal exchange server which is 172.0.0.2.

Exchange sees the address of the SMTP connection as source 172.0.0.1 and not 196.0.0.1; so lookups to RBL servers or SMTP blacklisting servers never get looked up.

Is there anyway I can get this sorted?

Thanks

2

196.0.0.1 172.0.0.1 if these you meant as local network addresses then you simply make routed network and exclude NAT from that destination

3

Hi,

Sorry if i was unclear – let me show u the topology

Mikrotik

Public Address: 196.0.0.6

Private Address: 172.0.0.1
Private network is: 172.0.0.0/24

If a mailserver- for example: http://www.example.com (196.0.1.1) connects to our address 196.0.0.6 to deliver mail - Mikrotik nat’s it to 172.0.0.2 which is our exchange server on the private network.

Exchange sees the source as 172.0.0.1 and not 196.0.1.1 ← which we want

4

post your firewall rules… you made a bugger up somewhere

5

Are you using src-nat? You want dst-nat - only change the destination IP.

Sam

6

src-nat sounds like it will work – it is currently using dst-nat

however it is still not working – i will have to play around more