Watch out for OCS filtering file transfers

I’m working on an Office Communications Server (OCS) 2007 pilot right now and have started to use Office Communicator 2007. I’m really impressed (and will write something soon about the whole unified communications setup – including voice and e-mail integration); however two things that tripped me up were the addition of a _ prefix on URLs to prevent them from being clickable (just something to bear in mind when sending instructions to someone via IM) and the filtering of attachments during file transfers.

Neither of these are new features but the file transfer filtering caught me out twice when I thought someone had sent me a Windows registry (.reg) file (it had been turned into a text file contain the text “This attachment was removed.”) and then when another colleague sent me a compressed folder (.zip file) containing an ASP.NET website that I needed to deploy, only for me to find that even though the compressed folder had the complete file structure in its index certificates (.cer/.p7b files), .vb and .js files had all been removed and were not available for extraction.

I’m pretty sure that this behaviour can be changed if required (I’m not sure if it’s granular enough to change on a personal/team/company/public basis) but nevertheless it’s something to be aware of.

2 thoughts on “Watch out for OCS filtering file transfers

  1. Hi Mark,

    Are you working on Standard or Enterprise? How many servers? IF you get a chance to simplify the explanation on the required certs (e.g. do we really need it, can we just rely on external certs only, etc), and exact DNS records to create for internal and external, etc? There are guides out there including MS, but deciphering the information without trying to deploy it is like leading the blind through a maze! Good Luck with your pilot.



  2. LL,

    We’re using standard edition (not many users on this system) and I imagine that’s what the majority of deployments will use until either IM/VOIP/conferencing technology becomes “mission critical” (as e-mail has over recent years) or unless they have many thousands of users (I’m not sure what the figures are for OCS, but certainly LCS was reckoned to support up to 20,000 users on a single standard edition server).

    When I get some time, I’ll write a post about my experiences of getting this up and running and I’ll try to include something about the certificate choices but basically if you have an internal CA that is in the trusted CA list for your users then you should have no problems – if you stick with external certificates then the clients will probably trust the CA, but you may spend a lot of money buying multiple certificates – in which case a wildcard certificate might be more appropriate.

    HTH, Mark

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