Sending Bulk Mails

[Goutam Baul]

Dear List,

We are running our mailing system using Postfix (postfix-2.0.16-14.RHEL3).
We need to send communications to our shareholders (around 15000 of them)
using the mailing system. If we simply send the mails using things like
phpmailer etc. then we fear that

1)       1)       There could be an issue with the server performance as
because these many numbers of mails will be pushed to the queue at the same
time. This can, however, be addressed by tweaking the mail sending script
carefully.
2)       2)       Some of the receiving domains like yahoo etc. might think
that we are creating spam and blacklist us.

We don’t have any idea on how many mails should be safe to push per hour so
that our servers don’t face the risk of getting blacklisted. Is there any
threshold value?

Would anyone advice us on the correct approach that we should take? This is
going to be a regular feature in our operations and we need to device a good
solution. Any help please.

With regards,

Goutam