From: Buenos Aires, Argentina
Hello and thank you in advance for your help.
I have 2 internet conection. One is the main connection, the other is used when the first fails. Second connection is a backup.
While using the main connection I have no problems. When I use the backup connection, because the principal stopped working, when sending emails, I get an error because the internet provider of this connection requires me to use their own SMTP servers.
I wonder if I can create a rule to activate when I'm with the backup connection, which directs all SMTP traffic to the SMTP server of our provider, regardless of what each user has set their SMTP email client.
When I return to the main connection, under that rule and go.
From: Taylorville, IL
No. That is not possible.
It would be a waste of time anyway because that other ISP is going to be using a different IP so the Reverse DNS Lookups used by Anti-SPAM systems is going to fail and your outbound mail would be rejected. Secondly your MX Record is still pointing to the original ISP so you would not receive any incoming mail. You can run dual MX Records with Preferences set,...but that is "clunky" at best.
The "right" way to have redundancy is to have two links to the same ISP,...and the ISP performs the redundancy (not you),...hence no matter what link is up or down your Public IP# does not change.