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Tag Archives: Lync

Using Avaya IPO as sip trunk with Lync – problems dialling international and cellphone numbers

After connecting Avaya IPO to our Lync infrastructure we discovered that long distance calls from Lync often failed, especially to cell phones/mobiles – usually with a “cannot accept call 405”.

Thanks to this:

I discovered it’s due to Lync giving up on calls through the pstn after 10 seconds! change the config file referenced here so the timeout is 20 seconds and restart server (or just front end and mediation service) and your issue will be resolved.


Credentials are required, calendar password prompt – Lync/Communicator

If you find users are unable to dismiss credential prompts from communicator or Lync that reference calendar access, even if entering correct password and you are running Checkpoint IPS, it’s likely that the non-compliant http protection is blocking its calendar access through your companies address. To stop this behaviour, enable an exception for the non-compliant http IPS protection between your reverse proxy’s internal nic and your CAS and your firewall and the published proxy nic/ip.

Should you find you are continued to be prompted for credentials (which are dismissed after you enter them) when connecting from outside the LAN after this change or DO NOT use checkpoint’s IPS, please look at this post – it fixed things for me: Many thanks for this!

Self Signed Certificates Issued to Polycom Lync Phone Devices – causes additional certificate authentication pop-ups for other certificate dependent services

Woohoo – this is fixed, go here for the hotfix: 


Posted this, here: a while back, anyone else having same problem? Off the back of another support call I spoke with an escalation engineer and he agreed that it was a significant issue, but couldnt confirm when it would be resolved. Do let me know if you’ve found a way for these polycom devices and 802.1x eap authentication to work without irritating popups.


Hi there,

I’ve just configured a pilot Lync2010 pool with the eventual intention of deploying lync handsets across the organisation.

Everything seems to work great, delighted with the polycom hardware (cx600).

However, when i sign into Lync, and my device retrieves a certificate (that seems to be deposited in my personal cert store as well), this certificate causes problems with:

-EAP wireless

-EAP authentication to the vpn

What happens is when i connect to wireless i now have to choose between my lync cert and the company cert, the lync cert is not trusted as is not issued by a trusted authority (clearly). This isnt a big deal to me but extra prompts are a major deployment blocker for my users!

Is there no way to get Lync to use certificates issued from our enterprise CA as opposed to it’s own, then we’d have a single personal certificate for all these services?

Using DHCPUtil.exe i have pointed my device at my ent CA, but it still gathers a self-signed cert from the lync server.

I dont believe i’m the only person to run into this issue:


Lync Server with Polycom phones VM Lab.

We got a couple of Polycom phones for Lync for review, set them up off the back of a lab in VMWare Workstation. Struggled to figure how to configure it physically given i needed it to be portable and all run off my laptop whilst i was also connected to my network, to get round this i used a usb ethernet adaptor bridged to one of the vmnet nics to connect a switch to the sandbox network and then the phones into that.

The voice quality seems superb, and the automation/integration with the Lync desktop client works lovely.