Hi everyone,
I tried to make redundant send connectors with 2 internet connections, so that in case one connection down, I can still send and receive mails via the other one. But it's not working as expected.
Here's the scenario:
- I have 2 all-in-one mail servers (which means mailbox and CAS roles installed).
- Each server has a dedicated public IP.
- I created one send connector to send mail to the internet, with my 2 mail servers in theScoping/*Source server option.
- I tested by disconnect the public interface of one server's NIC (to simulate the case that the internet connection is down) and try to send mail. Some mails sent successfully, some never sent and bounced back to senders after some day.
I think using 2 source servers in only 1 send connector will not work, because mails will be sent by a mechanism like Round Robin, or sort of. So if one server in the connector cannot connect to the internet, mails routed to that server will be stucked there and cannot be sent.
On the other hand, using 2 send connectors, each connector has one mail server, and the connectors have different SMTP cost, will not work either, I think. Because in case the send connector with lower cost cannot send mail to internet, but the server associated with that send connector still up and running, the connector with higher cost will never be used.
The only way that might work is to use 2 NICs and 2 public IPs in only one mail server, so that mails will be routed to the correct server, and might be sent successfully. But I'm not so sure about that.
Sorry for my ridiculous English, but I hope everyone still understand my case. I would like to ask: if I have 2 internet connection with 2 public IPs, how could I configure the mail system so that mails can be sent to the internet when 1 internet connection down.
Thank you all.
