cannot log on to Windows Messenger from behind ISA Server

[edavlars]

I cannot log on to Windows Messenger from behind ISA
Server running on Windows Small Business Server 2003. I
can log on immediately when I am not behind the ISA
Server. I am using Windows Messenger Version 4.7.2009. I
never had any problem logging on from behind the ISA
Server running on Windows 2000 Server. I have checked all
security settings and port settings and everything
appears correct. When I click help on the login failure
message box, the report comes back that all the services
are running fine. I cannot find any reference to this
problem in the KB nor at ISAServer.org. Can someone help?

 

[pala]

if your ISA requires authentication than you should use
msnm 5.0 or above see details:
http://www.microsoft.com/technet/treeview/default.asp?
url=/technet/prodtechnol/isa/maintain/isaimsec.asp

but I can't make it work. I need to open my firewall at
port 1863 and set the msnm not to use proxy.

regards:
pala