Hotmail mail admin

I'm looking for a hotmail mail admin or someone with the information I'm
looking for.
I have a client that is trying to block the world, but only allow certain ip
addresses through. It looks like hotmail uses a large pool of ip addresses
for attachments so we've had a hard time determining what ip addresses to
allow. My client specifically is requesting this be allowed. Does anyone
know what addresses hotmail users for their attachment servers or would a
hotmail admin be willing to contact me off list with this information?

Thanks!

$ host -t txt hotmail.com
hotmail.com descriptive text "v=spf1 include:spf-a.hotmail.com
include:spf-b.hotmail.com include:spf-c.hotmail.com
include:spf-d.hotmail.com ~all"

$ host -t txt spf-a.hotmail.com
spf-a.hotmail.com descriptive text "v=spf1 ip4:209.240.192.0/19
ip4:65.52.0.0/14 ip4:131.107.0.0/16 ip4:157.54.0.0/15 ip4:157.56.0.0/14
ip4:157.60.0.0/16 ip4:167.220.0.0/16 ip4:204.79.135.0/24
ip4:204.79.188.0/24 ip4:204.79.252.0/24 ip4:207.46.0.0/16
ip4:199.2.137.0/24 ~all"
$ host -t txt spf-b.hotmail.com
spf-b.hotmail.com descriptive text "v=spf1 ip4:199.103.90.0/23
ip4:204.182.144.0/24 ip4:204.255.244.0/23 ip4:206.138.168.0/21
ip4:64.4.0.0/18 ip4:65.54.128.0/17 ip4:207.68.128.0/18
ip4:207.68.192.0/20 ip4:207.82.250.0/23 ip4:207.82.252.0/23
ip4:209.1.112.0/23 ~all"
$ host -t txt spf-c.hotmail.com
spf-c.hotmail.com descriptive text "v=spf1 ip4:209.185.128.0/23
ip4:209.185.130.0/23 ip4:209.185.240.0/22 ip4:216.32.180.0/22
ip4:216.32.240.0/22 ip4:216.33.148.0/22 ip4:216.33.151.0/24
ip4:216.33.236.0/22 ip4:216.33.240.0/22 ip4:216.200.206.0/24
ip4:204.95.96.0/20 ~all"
$ host -t txt spf-d.hotmail.com
spf-d.hotmail.com descriptive text "v=spf1 ip4:65.59.232.0/23
ip4:65.59.234.0/24 ip4:209.1.15.0/24 ip4:64.41.193.0/24
ip4:216.34.51.0/24 ~all"