Mail.com is the email division of 1 & 1 Mail and Media. Mail.com was formerly Outblaze.
There is very little information available about delivering to domains hosted by Mail.com.
Mail.com provides a postmaster page for email senders.
Mail.com does does not provide.
Mail.com does not offer a whitelist for senders.
Mail.com and other 1 & 1 domains use the Certified Senders Alliance whitelist in mail delivery decisions. Mail from IPs on the Certified Senders Alliance list are less likely to end up in the user’s spam folder.
Mail.com provides sender support through their contact form.
Mail.com has not published any information about commercial spamfilters they may use. They do reserve the right to use external and third-party blocklists, but do not