I was reading this Experts Exchange discussion, but it seem to stop without a solution. http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/Q_23652696.html?sfQueryTermInfo=1+exchang+isp+multipl
We are changing our ISP over which we send/receive email. During the DNS propagation time I would like to receive via our other ISP, but still send email originating in our office out the new ISP SMTP server. I figured all I needed to do was set up a second MX record.
But in testing if I telnet second_ip_address 25 from outside I get no response. Doing this internally within the lan works fine.
Can I get it to respond to email from both routers? I could just change the default gateway for a couple of days, if necessary, but I would like it for failover purposes.