I have dug through through the forum and found a few providers who do what we want.
DigBuddy is an email deliverability and MX monitoring service. Customers sign up and input all of the email addresses at their domain and our monitoring system will check to make sure that these email addresses are able to receive email by logging in and attempting to send an email without actually sending one. It also checks the DNS, SPF records and a bunch of other stuff so our clients can be assured that they are able to send and receive email to a variety of networks without issue.
We need to set up monitoring servers on a number of networks across a number of countries that can be used to send and receive email. Basically all we need is a VPS with 512mb of ram and 19 IP's. It also must have an unblocked SMTP port 25 and the IP's must have a neutral or better senderbase score. We also need to make sure that the IP's have proper forward and reverse DNS entries.
Does anyone have any recommendations of providers who can provide us with this service at a reasonable price?. Our budget is under $30.00 per month for this service all inclusive.
It hard to find a VPS with 512MB for that budget let alone that many IP since most providers restrict the number of IP you are allowed to have in a service (5 seems like the regular number for those limits).
I know fdcservers.net does not have any IP restriction but I haven't looked at their VPS in a long time but might be worth checking out. Just a note on them though their VPS systems are not the most powerful machines you have ever seen.
Well, I'm not sure if the provider can accept that kind of usage, InterServer have dual-core Atoms for US$39/mo (pretty close to what you need), the problem is: I don't know if they are ok with the "mail testing" thing, you would need to ask them.
Also, they give 5 IPs, and you have to pay extra for more. Why do you need 20 IPs on the same server for only monitoring? as far as I know, you only need additional IPs when you need to host many services which doesn't support virtual host (like SSL), or when you are going to sell VPSs and need 1 IP per VPS.