[CentOS] dovecot sieve rpm?

I don't know how firmly you want to stick with dovecot/postfix,
but an equivalent stack (cyrus/sendmail) is part of the base distro
and of course works well with sieve, is fast, and scalable.  Adding
Horde (which isn't part of the base distro) gives a good web-based
interface to sieve in addition to its usual webmail and other
features.

Devin