No Response from xxxx...

Rich Kennerly (rbk1@cornell.edu)
Tue, 01 Aug 1995 08:42:22 -0400


Here's part of the Windows FAQ on "No Response from x.x.x.x". We will be
doing something soon with the protocol to help diagnose firewall and IP
address 'proxy' problems.

>"No Response from <ip address>" error.
>
> Assuming that you have tested other winsock network applications so you
>know you have basic network connectivity, there are several possible reasons
>why you might be getting this response:
>
>* The reflector machine is down - Try to telnet, FTP, or PING the host
> address to check this. Even if you can't log in, any 'login' -type response
> will indicate that the host is on the net.
>
>* The reflector software is not currently running on the reflector host. Try
> a couple of reflector sites - it is not likely that too many will be down at
> the same time.
>
>* You have a 'firewall' somewhere at 'your end' - between your local network
> and the Internet. A firewall prevents traffic of certain types from
> passing in and out of a network or networks. For example, a 'firewall'
> may exist to reduce traffic volume by disallowing UDP packets - this will
> prevent PING and NFS (Network File System) packets from passing through.
> And, since CU-SeeMe uses UDP, it will not work either. It is also possible
> for a firewall to disallow certain UDP port and allow others. Your network
> provider can decide what type(s) of 'firewall' restrictions if any to
> impose on your network.
>
> It can be difficult to determine whether or not there is a firewall in
> place on your network. If you can telnet to a reflector host (even though
> you can't log on) but CU-SeeMe doesn't work then it could be a firewall.
> You can contact your network provider to see if there are any restrictions
> on the traffic passing in and out of your network. CU-SeeMe uses UDP
> (not TCP) on UDP port 7648. Or, if you're using a PC with Winsock, it
> could be:
>
>* There is a DNS IP address problem or 'proxy' DNS is being done. Somehow,
> with Winsock, it is possible for the machine to make a DNS query to the
> network for its own address which is not really the actual address of the
> Windows PC. CU-SeeMe uses this address in the CU-SeeMe packet header which
> is different from the address in the IP header (apparently). This can be
> caused by having two DNS servers with different IP addresses or, by a
> machine doing 'proxy' DNS where it claims to be 'you' so it will get
> your packets which it will then forward to you. This latter example has
> been found in a situation where SLIP IP addresses were being 'spoken for'
> by the slip server. Unfortunately, we don't have good information about
> what can be done to really solve this problem. I would recommend having
> your host and actual IP address in a HOSTS file locally so the DNS call
> is either not made or not favored over the local hosts entry.
>
>

-Rich Kennerly - <rbk1@cornell.edu> PC Windows CU-SeeMe developer

------- Forwarded Message

Date: Mon, 31 Jul 1995 18:04:12 -0500 (CDT)
From: Cyber-Q <lockheed@fc.net>
To: <CU-SEEME-L@cornell.edu>
Subject: Re: What have I done wrong?

I've had the exact same problem, as well as quite a few other PC-users it
would seem. It's hard to tell if it's a problem with the clients (Mine
was working fine, v0.65b2) or with the reflectors - I know there's been a
recent new release of the reflectors - could there be an incompatibility
between the PC-clients and the new reflector release?

Right now I'm just on HOLD waiting for the next PC-client release, hoping
maybe it clears up with that new version. Otherwise... <shrug>

- --Steve

> I have been using Cu-Seeme for Windoze successfully for close to a year now with a
> dialup PPP account. Just recently when trying to access a reflector (any reflector) I get
> the "no response from xxxx" error message. This occurs on all reflectors including
> Cornell and Nysernet. I can ping these reflectors so I know they're still out there.
> All of my other internet clients are working properly and msvideo.dll and ctl3d.dll are
> still in the \windows\system directory (and nowhere else).
> I have even re-installed the software and started over with a "fresh" cuseeme.ini file
> Still no help..... I'm running out of ideas....
> Any thoughts would be greatly appreciated.
> -------------------------------------
> Steve Miller
> E-mail: smiller@onramp.net

|----------------------------------------------------------------------------|
| Steven B. Kirk | DT Systems Performance Analyst | Systems Administrator |
| | Dell Computer Corporation | MultiComm - Las Vegas |
| lockheed@fc.net | steven_kirk@ccmail.us.dell.com | lockheed@unix.mclv.net |
|------------ URL: http://www.mclv.net/staff/lockheed/home.html -------------|

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