I want to know if there is a firewall port policies set of connecting using using Microsoft Lync for Mac 2011. I noticed that if I connect using Microsoft Lync for Mac 2011 from within my corporate network, if fails. At times it connects and immediately fails. But when when I connect from outside my office network it works fine

Are you using an internally signed certificate?  If so, it is installed correctly in the Mac's keychain?  See Georg's excellent write-up here: http://www.lynced.com.au/2014/06/install-root-certificate-on-mac-osx-for.html

I agree with Anthony, we have plenty of Mac's and since they are not domain members they don't automatically get the internal Root CA. Just follow George's widom and you will be sorted

The certificate was previously installed. The thing is, machine logs on occasionally and after sometime, it disconnects. Is there is firewall port number that is set by Microsoft which it allows Lync on Mac communicate through? 

Hi,

Did you enable Kerberos authentication for Lync Mac?

When connected to the internal corporate network (LAN), make sure enable Kerberos authentication for Lync for Mac, verify that the Kerberos plug-in has been enabled in Mac OS X and is working correctly.

More details:

http://blogs.technet.com/b/nexthop/archive/2011/11/10/troubleshooting-for-lync-for-mac-2011-with-lync-server-2010.aspx

Best Regards,

Eason Huang

The Lync client typically uses TCP port 5061 for network communications in an on-premises environment.

Also check below link

http://jackstromberg.com/2012/10/lync-2010-server-lync-2011-for-mac-clients-failing-to-connect/

http://technet.microsoft.com/en-us/library/jj945442%28v=office.14%29.aspx

Wanted to know if  there is a TCP port typically used by lync for O365.