That was really hard night – we migrate one of our customer to version 7.0.2 and tried to create a failover way for sending SMTP emails outside company. And it doesn’t work, we spent a lot of time with it without any success.
What we did? We have one Foreign SMTP domain and two different connection documents from one server to this domain. One connection document has routing cost 1 (or 0, never mind) and is connected directly to internet. The second one has routing cost 2 (or 1, depends on the first one) and routes all emails to specific IP address (relay).
When you look at help, Domino should take the cheapest one and try to route mail. If it will be unsuccessful that it should wait few minutes (you can specify it in Configuration document) and should try more expensive connection document. But it never happened. And it is much worst – Domino took the first connection document from view, not the cheapest one.
We reported it to IBM and it’s really a bug with PBR MHUC6ZPKVB and SPR ESTN5XFPTP.
How to solve it?
There is still one way you can use failover for email routing and you need relay hosts for this way (you cannot send emails directly to internet). If you want to use this, just route emails to relay and in DNS (or hosts file on Windows) specify to different IP addresses for this relay. Windows (sorry, we tried it on them) will use the first IP address and if it’ll be unsuccessful then try the second (third, ….) IP address. But it isn’t Domino functionality, but OS functionality 🙁