Hi,
Hit Interspire mods dot net for advance level configuration of an email server. Email delivery to inbox requires reliable application and experience of configuring the infrastructure according to the standards of mailing industry, configuration as devised by major ISPs for commercial mailing and in compliance with spam act.
for 100k plus emails, a dedicated server is required and recommended, but can only a dedicated server with its resources allocated exclusively for you guarantee success? and the answer is no, a sending infrastructure is required with bunch of advance features for list management, monitoring and scheduling, with implementation of appropriate SMTP gateway, DNS management with implementation of txt records/ mail authentications is an important factor also. Once the server is well configured, you need to follow the best practices of sending, for first increasing the reputation of your IPs and then maintaining it.
If you are looking for email server setup and configuration,fell free to hit me up adnan.ahmed227 @ Skype.