i found the service for backup of SMTP:
If your mail server or network goes down, our backup SMTP can receive and store your incoming e-mail for up to 30 days. E-mail and ecommerce orders will keep coming, giving your IT staff time to repair the problem. Our standard service reattempts delivery every 15 minutes until your mail server is back online.
Seems that is good decision if you want to provide quality services for your cusutmers, but i want to know your opinion regarding this service or similar.
did you use services like this , and can you share some experience for this?