Set up your network for Skype for Business Online operated by 21Vianet

Note: This article applies only to Office 365 operated by 21Vianet in China. All other customers should see Set up Skype for Business Online.

To set up your network for Skype for Business Online:

1. Add CNAME (alias) and SRV (service) settings to your Domain Name System (DNS) server.

2. If you have an external firewall or proxy server, configure it to allow Skype for Business traffic.

3. Test your DNS and firewall settings.

Step One: Add DNS settings

If you're using your own domain name, add these entries to your external DNS server:

Type	Host name	Destination	TTL
CNAME	sip	sipdir.online.partner.lync.cn	1 hour
CNAME	lyncdiscover	webdir.online.partner.lync.cn	1 hour

Type	Service	Protocol	Port	Weight	Priority	TTL	Name	Target
SRV	_sip	_tls	443	1	100	1 hour	yourDomainName	sipdir.online.partner.lync.cn
SRV	_sipfederationtls	_tcp	5061	1	100	1 hour	yourDomainName	sipfed.online.partner.lync.cn

See DNS setting details for the features affected by each record.

If you have a firewall that blocks external SRV queries, add these entries to your internal DNS server as well:

Type	Host name	Destination	TTL
CNAME	sip	sipdir.online.partner.lync.cn	1 hour
CNAME	lyncdiscoverinternal	webdir.online.partner.lync.cn	1 hour

Type	Service	Protocol	Port	Weight	Priority	TTL	Name	Target
SRV	_sip	_tls	443	1	100	1 hour	yourDomainName	sipdir.online.partner.lync.cn

Step Two: Configure your firewall or proxy server

If you have an external firewall or proxy server, define rules for Skype for Businessports, outgoing connections, and IP address ranges.

Ports

Open the following ports in your organization's external firewall:

Port	Protocol	Direction	Usage
443	STUN/TCP	Outbound	Audio, video, and application sharing sessions
443	PSOM/TLS	Outbound	Data sharing sessions
3478	STUN/UDP	Outbound	Audio and video sessions
5223	TCP	Outbound	Skype for Business mobile push notifications
50000-59999	RTP/UDP	Outbound	Audio and video sessions

Outgoing connections

Create a rule that allows outgoing connections (TLS and HTTPS) for all users to these locations:

• pipe.skype.com

• skypemaprdsitus.trafficmanager.net

• *.partner.microsoftonline.cn

• *.partner.microsoftonline-p.cn

• *.onmschina.cn

• *.sharepoint.cn

• *partner.outlook.cn

• *partner.lync.cn

Set the HTTP/SSL time-out value to eight hours.

IP address ranges

See URLs and IP address ranges for Office 365 operated by 21Vianet.

Step Three: Test your settings

Test your DNS settings:

1. Go to the Microsoft Remote Connectivity Analyzer.

2. On the Office 365 tab, choose Office 365 Skype for Business Domain Name Server (DNS) Connectivity Test, and then click Next.

3. Enter the sign-in address that you use when you sign in to Skype for Business Online (for example, bob@contoso.com), and then start the test.

DNS setting details

This table shows the Skype for Business features affected by each DNS setting.

Type	Host name or service	Features affected
CNAME	sip	Skype for Business desktop client autodiscover and sign-in
CNAME	lyncdiscover lyncdiscoverinternal	Skype for Business mobile client autodiscover and sign-in
SRV	_sip	Skype for Business IM and presence integration with Outlook Web App Authenticated user sign-in with Lync Web App
SRV	_sipfederationtls	Supports adding Skype for Business users in other organizations to the Skype for Business Contacts list.