I have commented on the related thread, with my situation
here is my comment:
"i'm sorry but this is not a solution, it's a workaround
this problem is completely dubious.
3 years past this post, it happens to me, on xp sp3
it's so spurious . . why has nobody else complained about this
port forwarding will not work
firewall is off
i telnet to the machine with the service on the internal port, in the interior lan, it works.
from the same machine i telnet to the external adress and external port yet it does not get through
i've switched with another ics server, the same conditions, sp3 uptodate
the same thing happens - what am i missing??
one peculiar thing i do is set a false MAC for the external NIC to get service from the isp
but this can't and shouldn't impact on port forwarding"
thank you to anybody willing to read that description and answers, and to suggest causes for this issue