when I send mail to gmail through SMTP I got a erro
follow the link it said
'The IP you're using to send email is not authorized...'
In order to prevent spam, Gmail refuses mail when the sending IP address does not match the sending domain. To send mail from your server to Gmail, we suggest using the SMTP relay provided by your ISP. Please note that we are unable to whitelist IP addresses or otherwise make exceptions at this time.
It seams that, gmail will test my ip with MX record, (for this test, I send from localhost), but if myhost.com has 3 MX record, will google test each MX to match my ip, or is there any way to bind a domain to a ip, not bind an ip to a domain.
After google, I think the most import thing is set DNS PTR.