Hotmail blackholing certain IP ranges ?

Jeroen Wunnink wrote:

Does anyone have a clue why hotmail is appearantly blocking certain IP ranges ?

I provided a new server for a customer in his own IP subnet which is a part of a /20 we announce, but for some reason all mail sent to addresses disappears.

He has another server in a /24 we announce which is still part of another network and that works like a charm.

None of our subnets are blacklisted in any spamfilter I can find, so i'm a bit puzzeled on what's up here.

If any hotmail netadmin is reading this list, can you please check if is blocked in any way (It's part of originating from AS39556)

According to the mailserver logs all the mail is properly accepted by the hotmail relays, never to be seen again after that.

hotmail reportedly installed some new spam control lately.
many ISPs and ESPs are reporting problems similar to what you describe
(my employer is having such deliverability problems, for one.)

SPF records, signing up for the MSN/Hotmail feedback loop, and opening
a ticket with hotmail support are all things you can do. effectiveness
is not guaranteed, and it's taking hotmail 3-4 days to respond to new
tickets, they appear to be swamped.