回复：I found that ipkall blocked the number from 1/28/2010

there is also one made complaint about the blockage on his ipkall number on Jan 28th. my sipgate record shows that from Jan 28th, sipgate resumed to send out the call to me.

Here is their anuncement on which sip provider can use their DID as USERID:
Important Announcement:
You can now configure our FREE US phone numbers with the following discount VoIP services: Free World Dialup FREE
(fwd.pulver.com)
Pennytel
(sip.pennytel.com)
Inphonex
(sip.inphonex.com)
Gizmo Project FREE
(proxy01.sipphone.com)
SIPphone FREE
(proxy01.sipphone.com)
Iconnecthere
(sipauth.deltathree.com)
FonoSIP
(fonosip.com)
Vbuzzer FREE
(vbuzzer.com:80)
Callcentric FREE
(in.callcentric.com)
Nikotel
(calamar0.nikotel.com)
CallWithUs FREE
(sip.callwithus.com)


Please be aware that all accounts require a valid email address in order to receive your IPKall number. Accounts with invalid email addresses will be terminated. Accounts which are inactive for 30 days may be terminated for non-use.
To sign up for your own personal phone number, simply fill out the form below with your existing SIP phone number. You will need to set up an account with one of the above VoIP SIP provider before you can receive a free number.