Because IM uses SIP signaling for voice and video. That breaks when the caller is behind any NAT device. Jim Harrison MCP(NT4, W2K), A+, Network+, PCG http://www.microsoft.com/isaserver http://isaserver.org/Jim_Harrison http://isatools.org Read the help, books and articles! ----- Original Message ----- From: "Rafael Narezzi" <rafael@xxxxxxxxxx> To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx> Sent: Monday, February 10, 2003 11:42 Subject: [isalist] MSN VOICE http://www.ISAserver.org Hi Guys, I would Like to know why my msn work when the people call me but when I call the people my firewall ISA SERVER BLOCK ?? What's Heppend SEI - Soluções em Informatica J. Rafael Narezzi It Manager rafael@xxxxxxxxxx http://www.sei.inf.br http://www.indaia.net ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Exchange Server Resource Site: http://www.msexchange.org/ Windows Security Resource Site: http://www.windowsecurity.com/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: jim@xxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')