This is where they've gone wrong (You'd think they'd know how DNS works....)
They are 'honouring' updates to the users dynamic addresses, but in a horrible and incorrect way:
The authoritative nameservers are configured as recursive for *ALL* domains (yuck)
They have configured an override to divert forwarding requests for these affected domains to the no-ip (original) authoritative nameservers. (i.e. they've statically added NS records for the affected domains pointing to the no-ip servers)
They therefore reply to the client with the correct IP address.
This would be fine for a recursive nameserver, but these servers are configured as *authoritative* nameservers for these domains - and are accessed as such, but they are returning the result as non-authoritative.
Basically, this creates the following process (Example uses the no-ip.org domain, but the same applies to the others. Some irrelevent steps skipped/simplified) :
1) User requests the IP for some-subdomain.no-ip.org
2) Users local nameserver (usually belonging to their ISP) checks the .org servers and is told that the 2 microsoft nameservers are responsible for this domain.
3) Users local nameserver ask the microsoft servers for the authoritative ip address of the subdomain, only to be given an unauthoritative result, along with the message 'if you want an authoritative result, go here' which points BACK to the same microsoft nameservers.
4) Users local nameserver replies with SERVFAIL because the nameserver that is meant to be authoritative is not returning an authoritative response.
Whichever bozo claimed everything is working presumably just did a 'raw' nslookup, saw the response, and didn't think (or know) about authoritative/non-authoritative results.
Or maybe MS nameservers don't handle authoritative/non-authoritative results correctly, so things 'work' if your ISP uses a microsoft nameserver product?? I don't know, just a guess...
Anyway, MS, I think this post is worth many thousands of your MS dollars!
By way of an example, here's a session capture using a jo-ip.org domain chosen at random:
4:37 [2] (1) "~" jamie@lapcat% nslookup
> server a.root-servers.net.
Default server: a.root-servers.net.
Address: 2001:503:ba3e::2:30#53
Default server: a.root-servers.net.
Address: 198.41.0.4#53
>
> home.no-ip.org.
Server: a.root-servers.net.
Address: 2001:503:ba3e::2:30#53
Non-authoritative answer:
*** Can't find home.no-ip.org.: No answer
> set q=ns
> home.no-ip.org.
Server: a.root-servers.net.
Address: 2001:503:ba3e::2:30#53
Non-authoritative answer:
*** Can't find home.no-ip.org.: No answer
Authoritative answers can be found from:
org nameserver = a0.org.afilias-nst.info.
org nameserver = a2.org.afilias-nst.info.
org nameserver = b0.org.afilias-nst.org.
org nameserver = b2.org.afilias-nst.org.
org nameserver = c0.org.afilias-nst.info.
org nameserver = d0.org.afilias-nst.org.
a0.org.afilias-nst.info internet address = 199.19.56.1
a2.org.afilias-nst.info internet address = 199.249.112.1
b0.org.afilias-nst.org internet address = 199.19.54.1
b2.org.afilias-nst.org internet address = 199.249.120.1
c0.org.afilias-nst.info internet address = 199.19.53.1
d0.org.afilias-nst.org internet address = 199.19.57.1
a0.org.afilias-nst.info has AAAA address 2001:500:e::1
a2.org.afilias-nst.info has AAAA address 2001:500:40::1
b0.org.afilias-nst.org has AAAA address 2001:500:c::1
b2.org.afilias-nst.org has AAAA address 2001:500:48::1
c0.org.afilias-nst.info has AAAA address 2001:500:b::1
d0.org.afilias-nst.org has AAAA address 2001:500:f::1
>
> server 199.19.56.1
Default server: 199.19.56.1
Address: 199.19.56.1#53
> home.no-ip.org.
Server: 199.19.56.1
Address: 199.19.56.1#53
Non-authoritative answer:
*** Can't find home.no-ip.org.: No answer
Authoritative answers can be found from:
no-ip.org nameserver = ns7.microsoftinternetsafety.net.
no-ip.org nameserver = ns8.microsoftinternetsafety.net.
> server ns7.microsoftinternetsafety.net
Default server: ns7.microsoftinternetsafety.net
Address: 157.56.78.73#53
> home.no-ip.org.
Server: ns7.microsoftinternetsafety.net
Address: 157.56.78.73#53
Non-authoritative answer:
home.no-ip.org nameserver = ns7.microsoftinternetsafety.net.
home.no-ip.org nameserver = ns8.microsoftinternetsafety.net.
Authoritative answers can be found from:
> set q=a
> home.no-ip.org.
Server: ns7.microsoftinternetsafety.net
Address: 157.56.78.73#53
Non-authoritative answer:
Name: home.no-ip.org
Address: 85.241.47.150