in one of our setups we have several outgoing internet lines. Due to various reasons we are forcing exim to send mail via one line only. Unfortunately exim is not going to see if that line goes down. Usually I would solve this on the networking level but in this setup it does not seem feasable. What I would like would be something like this in a transport
interface = firstadress : secondadress
If Exim is not able to connect on the first interface (TCP connect that is) it should try the second interface automatically as a fallback interface (similar to fallback host). Is this possible somehow and if not could this be added to the whish list please?