Re: Bug#207300: tmda: Challenge-response is fundamentally broken
On Sat, Aug 30, 2003 at 04:01:19PM +1000, Russell Coker wrote:
> Backup MX servers serve no useful purpose in the modern Internet, this is why
> big sites such as microsoft.com and hotmail.com don't have them.
> If you have a backup MX then it should know all the acceptable email
> addresses in your domain and enforce all rules regarding acceptable content.
> Then it can block content through SMTP 550 and 450 codes.
if you don't have 100% administrative control over your backup MX server(s) then you
should NOT be using them.