Direct Routing SIP signaling FQDNs

[Balaji NJL]

Hi,

https://docs.microsoft.com/en-us/microsoftteams/direct-routing-plan#sip-signaling-fqdns

The above document has been updated recently and it states 

The FQDNs – sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com and sip3.pstnhub.microsoft.com – will be resolved to IP addresses from the following subnets:

• 52.112.0.0/14
• 52.120.0.0/14

But when you do a nslookup for sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com and sip3.pstnhub.microsoft.com, none of them resolve to any of the above subnets. I distinctly remember previously the list of IP address used to be

52.114.7.24, 52.114.132.46, 52.114.75.24, 52.114.76.76, 52.114.148.0, 52.114.14.70,

52.114.16.74, 52.114.20.29, 52.112.0.0/14

Can someone from Microsoft clarify this. I don't see 52.114.x.x subnet in the documentation. 
Thanks,

-Balaji

[#2]

@Balaji NJL 

See here

Azure direct routing infrastructure requirements - Azure Communication Services | Microsoft Docs

The FQDNs – sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com, and sip3.pstnhub.microsoft.com – will be resolved to one of the following IP addresses:

• 52.114.148.0
• 52.114.132.46
• 52.114.75.24
• 52.114.76.76
• 52.114.7.24
• 52.114.14.70
• 52.114.16.74
• 52.114.20.29

Hope that answers your question :D

Best, Chris

[#3]

Thanks @Christopher Hoard for your quick reply. Yes, these are the IPs I had originally. Even though both document got updated on 06/30/2021, the IP address list seems to be incorrect on the one that I referred.

[#4 · Accepted solution]

You may want to check a subnet calculator
52.112.0.0/14 contains 52.112.0.0 - 52.115.255.255
It includes the 52.114.x.x range.

[#5]

You are right, I didn't realize /14 covers 52.114.x.x. Thanks for pointing it out.