Since around 11:30am GMT this morning hotmail has not been accepting any inbound email for hotmail.com, .co.uk live or msn domains.

When an SMTP server trys to make a connection to any of hotmail MX servers the connection is either accepted and then closed immediately or outright rejected.

There is nothing on the hotmail/Microsoft postmaster site to acknowledge the problem at this stage however it has been reported on twitter that it may be down for as long as 8 hours which allegedly came from a Microsoft technical support representative.

Mail server administrators should monitor outbound queue sizes and take measures to protect their email infrastructure in the event that their queues become too large/full.

If you have any further information on the issue please leave a comment so that it can be shared with other readers.