How can a Lync Server be used for external communications

There are various ways to configure Microsoft Lync Server, now Skype for Business, to allow internal Lync users to communicate with someone outside of the company.  In the Lync Server architecture, it is the Edge Server role that enables all remote connectivity scenarios. The Edge Server in Lync 2013 is actually three consolidated services: Access Edge, Web Conferencing Edge and Audio/Video Edge. Lync Server 2013 Edge can also be configured as an XMPP Proxy. In addition to the Edge Server role, a reverse proxy server is required to allow external Web service communications to take place with the internal Lync Servers. It is possible to deploy an Office Web App server to stream content -- such as PowerPoint presentations -- to internal and external conferencing participants. Configuring remote connectivity is one of the more challenging aspects of deploying Lync Server for administrators.

Edge services are typically customized to meet an organization's requirements. In other words, not every organization will allow all forms of external communications. Some organizations may even opt not to deploy the Edge role at all. Here is a list of external communications supported by Lync Server 2013 Edge Servers:

·         Remote Lync Users: Employees outside the company network/firewall.

·         Lync Federation: Other companies running Lync Servers configured to allow your company to communicate with them and your organization allows them to communicate with you.

·         Skype Federation: Companies that register their organizations for public IM connectivity can configure Lync Server to allow their users to communicate with Skype users.

·         XMPP Federation: Extensible Messaging and Presence Protocol is an open standard supported by Lync Server that lets Lync users communicate with XMPP-based communication platforms.

·         Office 365: Organizations that have Lync Server deployed on-premises or the cloud-based version in Office 365 can benefit from a hybrid configuration, allowing a shared SIP domain name and more.

Even when all the external communications are configured for an organization, not everyone in a company will be able to use them. There are a number of external access policy configurations that govern communications for a Lync organization. Also, the type of Lync client you are using could have an effect on the types of communications supported.

It is also worth noting that you can invite an external user to join a Lync Online meeting even if they are not federated with your company. However, conferencing policies must be configured to allow anonymous connections. People working outside a company can connect to meetings through the full-featured Lync Web App client.