Bill Woodland (
Sat, 30 Dec 1995 01:25:29 -0600

At 08:25 PM 12/29/95 +0100, you wrote:
>>but my problem is due to Dutch providers who have banned the use of
>>CU-SeeMe from the net. Try to check with your provider first.
>How does this actually happen? How do you block a CU-SeeMe signal and
>allow the rest to pass?
>Just curious

Their router has what is called a "firewall" that blocks UDP packets, which
is what CU-SeeMe uses to send its data. They might even block only UDP port
7648. The following info is straight from the readme.txt file:

CU-SeeMe uses the UDP protocol. This is different from most TCP/IP
applications which use TCP. UDP is used by NFS (Network File System)
and PING and a few other programs.

CU-SeeMe uses UDP socket 7648. Some network providers have "firewalls"
installed that prevent UDP traffic such as CU-SeeMe from flowing. Some
of these providers are willing to remove the firewall for you if you
ask, some are not. There is more information about firewalls in FAQ.TXT.

Bill Woodland (
Squeek on Undernet IRC
Channel Manager #CU-SeeMe