Windows 2012 R2 server fails to establish outbound connections

Hi there, It’s been a very long while since I have blogged something here and it’s time to come back and continue sharing our field experiences with the IT community hoping to shed light for similar problems. I was tasked to deal with a customer problem where the end users were reporting various problems like “cannot access the…


Testing Lync server 2013 external URLs from Lync clients (external web service, meet, office webapps, lyncdiscover and dialin)

Hi there,   In this blog post, I’ll be talking about another powershell based tool which could be used to check name resolution, TCP layer connectivity and SSL/TLS negotiation for various URLs that are accessible through your reverse proxy which are:   – External web services URL – Meet URL – Office WebApps URL -…


Testing Exchange EWS service accessibility from internal/external Lync clients

Hi there,   In this blog post, I’ll be talking about a powershell based tool which could be used to check Exchange EWS connectivity especially from external Lync clients where the client might not be able to access Exchange EWS and hence cannot display meetings and similar.   The powershell tool uses Exchange EWS managed…


How it works on the wire: IIS HTTP Client certificate authentication

I collaborated with a colleague recently where the IE client was failing to authenticate to IIS and I was requested to analyze a few network traces collected while reproducing the issue. The main issue was that the client (IE) wasn’t able to successfully authenticate to IIS server when certificate authentication was configured on IIS side and was getting the…


DNS SRV lookup from Powershell

[After posting this blog, I have realized that Powershell 3.0 already provides a built-in cmdlet called Resolve-DnsName which could help you make any kind of DNS queries. But I still wanted to leave this blog post active for those who might want to see how it could be done with Win32 API. Also Powershell 3.0 is…


Testing STUN/TURN server connectivity from external networks through UDP 3478 by using Powershell

Hi there,   While working on a Lync connectivity test tool, I developed a STUN/TURN server connectivity test script in powershell which might be handy when you want to make sure that your external clients will be able to communicate with STUN/TURN server via UDP 3478 (STUN/TURN connectivity through TCP will also be added later on)….


External Lync 2013 clients cannot upload ppt or other files and whiteboard, poll, Q&A are greyed out on Lync client

Hi again,   In this blog post, I want to talk about a Lync 2013 problem where external users fail to upload powerpoint presentations. When external Lync user tries to upload a ppt file to an online meeting, basically nothing happens and once the failure occurs, all web conferencing related features are greyed out on…


Decrypting SSL/TLS sessions with Wireshark – Reloaded

Hi there,   In a previous blog post of mine, I went through the steps of decrypting SSL/TLS traffic by using wireshark and openssl tools. In this blog post, I wanted to talk about the same procedure again because it got even easier to decrypt encrypted traffic with Wireshark since then.  Here are the steps…


Running Lync 2013 WebApp plugin in locked down Terminal server environments

Hi there,   In this blog post, I would like to talk about running Lync 2013 Webapp in Windows Terminal server environments. Lync 2013 Webapp feature has a client side plug-in which provides audio/video/application sharing functionality and this plug is installed per user, in other words installation program installs files and creates registry settings in…


Event ID 56417 may be logged on Lync server 2013 intermittently

Hi again,   I dealt with a Lync server 2013 problem recently where the server was intermittently logging event ID 56417 in the Lync server event log:   – <System>   <Provider Name=”LS Data Collection” />   <EventID Qualifiers=”51423″>56417</EventID>   <Level>2</Level>   <Task>2271</Task>   <Keywords>0x80000000000000</Keywords>   <TimeCreated SystemTime=”2013-05-10T12:16:51.000000000Z” />   <EventRecordID>18850</EventRecordID>   <Channel>Lync Server</Channel>   <Computer>FE1.contoso.local</Computer>   <Security />   </System> – <EventData>   <Data>QoE…