We don't allow any mailing lists to be sent from any of our shared business email servers, but we do allow them to operate from our "Mailing List" email servers that will deal with bulk email accounts. Accounts on our Mailing List server are an additional cost.
Our anti-hijack system will automatically stop anyone sending out too many consecutive emails and if it is triggered it will stop ALL outgoing emails from that domain whether they were associated with the mailing list or not.
The anti-hijack thresholds are set so that they should not interfere with normal email delivery but they will shut-down anyone attempting to send too many emails within a specific period of time.
Small lists of less than 100 users will not be affected, but these small lists must operate a confirmed opt-in method of authentication. If you have obtained your mailing list from an affiliate or partner, or purchased the mailing list from a third party, then this would be unacceptable.
We do allow mailing lists to be sent from servers that have been designated as "mailing list" servers and these are available on some hosting accounts. Mailing List accounts are set-up manually and will only be allowed if we are satisfied that certain criteria are being met.