I want to use a custom email marketing, Double Opt-In managing and newsletter subscription management script hosted on my hosting account on your Reseller hosting plan. I want to know that does the major free email providers and email spam guard scripts & softwares makr the Email as spam based on the IP from which the email is sent or based on the Email Address?
What I would suggest for you is to use interspire self hosted email marketing tool it cost a bit, but it's worth to have it or there is services like aweber.
My webhosting provider don't allow to send email to Opt-In list. Suggest a cheap ($2-$4/month) hosting company which allows self hosted email marketing tool and I can send Bulk Emails to my Opt-In list.
hmmm that is really hard to fins, because mostly all web hosting companies have email restrictions. Use aweber you will end up paying the same money by using their service.
Email software is one thing to consider but there are some more important: smtp server, email list, spam traps, blacklist IP,.... It is not simply that you rent a software, have a list (good list is very costly, someone charge me about 1500/1mil double opt in if I buy high in volume)
There are free softwares and service, though paid ones like aweber, emailreach, mailchimp are the best site you can visit for this kind of queries.
Make a try on Email M - Email marketing service providers. Email M is a self hosted SaaS email marketing having multiple user friendly facilities. also now email M providing 30 days free trial for saas service. Make use of it.