Reverse connections originated from Win2k? (and details of a customer support CD)

Bryan A. Pendleton bpendleton "at"
Thu, 17 Aug 2000 22:33:50 +0000

I've been working on a simple client-support CD for the company I work for. 
Basically, the CD is an auto-launch disk that pops up a message, and, if 
the user elects to do so, opens up a reverse connection from the client's 
machine to our support personnel.

I've gotten most of the kinks worked out. I'll see if my boss will allow me 
to post code/etc. soon. It was really pretty simple.... package up the 
winVNC executable and .dll files, make a prototypical registry setup (with 
incoming connections disabled), and wrap it up with some scripts and 
verbiage so that it can run and exit with little impact to the system (it 
backs up the HKCU registry entries, installs its set, runs, and then 
restores when done. No programs are ever copied to the local hard drive). 
Nice and small, too... the whole package is only ~300kb.

And, it works pretty well, too. Since a lot of our customers are behind 
silly NAT-based corporate networks (DSL is huge locally, and most of our 
customers use that.... too bad the local DSL network changes your IP about 
3 1/2 times per day), the outgoing connection is a key element. And, that's 
fine (we have a block of static IPs, and a server with rinetd running. 
Basically, when a support call comes in, a tech uses a web interface to 
change the incoming connection to hit them, and we leave previous 
connections going. That way the CD can be set to always make its reverse 
connection to the same place).

Anyway, it works on WinNT(4sp6 is all I've tested, but I don't use anything 
weird enough to expect it to fail on anything besides the broken sp6, and 
pre-sp3 systems), Win95, and Win98. Pop in the CD, click through on the 
disclosure pop-up, and it fires away. No problem. But, on the one Windows 
2000 machine I've been able to test it on, everything works fine until the 
part when the reverse connection is being made... and the vncviewer (in 
listen mode) just pops up a dialog saying "Invalid protocol" and gives up.

I believe the machine is running Advanced Server, if that makes any 
difference. The connection is a mostly-local one. Ping and telnet work just 
fine from the machine. And, it reliably presents the "invalid protocol" 
dialog, so it's most likely related.

I searched the archives and didn't find anything that was helpful. Does 
anyone have any suggestions? Has anyone done reverse connections from Win2k 
to vncviewer in listen mode on Win95/98?


Bryan Pendleton
Phone: (877)780-3087
"The root of all knowledge lies within, but knowledge is useless unless it 
is collected and shared."
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