Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a scenario where there is a central office and several branch offices; there is already Active Directory in place, and each branch office has its local domain controller (no problems here).

The customer wants to deploy Lync Server 2010, together with the Lync client on each workstation. The plan is to deploy Lync front-end servers only in the central office, and have all clients connect to them.

The catch is, there is absolutely no routing between the branch offices; they are not meant to directly talk to each other, only with the central office.

Now, as everyone knows, Lync clients are only managed by the Lync servers, but talk directly between themselves for actual communications; unless of course a conference is involved, in which case they connect all to the front-end servers which acts as a MCU.

In this scenario, where there is no connectivity between branch offices, will two Lync clients in two different offices be able to talk to each other? Will they automatically fall back to connecting through the front-end servers, or will they just refuse to connect at all?

share|improve this question
May I ask why they enforce such a policy? Why not lease IP VPN (GRE over MPLS) with QoS to do this properly? – pauska Jul 29 '11 at 18:12
Because they are completely crazy about fake security (and don't actually understand anything about real one). They even use Outlook as a POP3 client because they don't want to open RPC to the Exchange servers. It was a pain just to make them acknowledge that you actually have to enable traffic to Lync Front-End servers in order to use Lync at all. – Massimo Jul 29 '11 at 18:31
My....head..... – pauska Jul 29 '11 at 18:32
up vote 2 down vote accepted

This can be done with an Edge server. Once a Lync front-end is deployed you can rollout an edge server. This will allow for a number of things federation with other Lync users, connectivity to external IM services like AIM, MSN and Jabber/XMPP clients, as well as external access for users.

Here is the MS deployment guide:

share|improve this answer
I know what Edge servers are for... but are they needed also for internal users (i.e. users that can talk with Front-End servers), when they don't have direct connectivity between them? – Massimo Jul 29 '11 at 17:18
They are needed for any client who can't directly talk to another client. – pauska Jul 29 '11 at 18:11
Ok, thanks. Just a little clarification: in this scenario, will internal clients talk to the internal interface of the Edge servers or to the external one? – Massimo Jul 29 '11 at 18:28
@Massimo: I guess they will use the internal IP.. the most common way to set this up is by using split-brain DNS, so that internal clients use internal IP's and vice versa – pauska Jul 29 '11 at 18:35

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.