How can I block only Yahoo Messenger with ISA server?

How can I block only Yahoo Messenger with ISA server?

How can I block only Yahoo Messenger with ISA server?

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Yahoo uses http. You will need to block access to their servers. Here is the current list from yahoo:
  • Protocol: TCP or HTTP
  • Servers:
    scs.msg.yahoo.com
    scsa.msg.yahoo.com
    scsb.msg.yahoo.com
    scsc.msg.yahoo.com
  • Port: 20,23,25,80,119,5050,8001,8002

    This was first published in July 2003