Today afternoon, someone in the office ask me: it is possible to block MSN traffic in the office network?
Answer is Yes and No.
It is possible to block the official Internet Messaging (IM) IP addresses or port used by Yahoo/MSN/Skype.
However, there are lots of alternative ways to access blocked Yahoo/MSN Messenger.
Many online sites which offer access to Yahoo/MSN/Skype and other IM services online via web interface. Also, many tools and tweak available that allow people to access to IM systems as well.
IM Blocking : easier said than done.
Personally, I think that corporate IT Usage Policies represent the best way to deter employees from using instant messaging. Just trust the employee lah.
image source from The Straits Times dated 24 March 2011.