QMAILToaster / latest qmail to support DomainKeys, DKIM and SPF signout.
IP outbound rotation (random fashion acceptable)
Solution must be implemented in source code, so it can be compiled and deployed anywhere we need.
Developer must deliver detailed explantions on how to replicate build up and any thing that will be needed to have it done.
Solution must be able to be compiled on any Unix/FreeBSD distro.