Too many authentication failures

Hello!

We are using Xtightvnc to automate keystroke sending to an antique program running in DOSBox (btw, if anyone has better solutions for this, please do tell). Our VNC server is secured with a strong password, but accepts connections from 0.0.0.0/0.

We ran into a problem of "Too many authentication failures" because bots and scanners from the internet were trying passwords on our VNC server and after 5 tried passwords, our automation software couldn't log in anymore to perform it's tasks. We added a firewall as a temporary measure, but today we broke the firewall and bots broke our automation again.

It would be really useful to us if "Too many authentication failures" security feature could be disabled (== if user could set the value of MAX_AUTH_TRIES himself). We don't want auth bruteforcing to cause denial of service so easily.

Is this already somehow possible in current Xtightvnc (Debian)? If not, are you accepting contribution in form of patches to your project?

I can't find a way to disable this, even after looking at the source code in vnc_unixsrc/Xvnc/programs/Xserver/hw/vnc/auth.c:

/*********************************************************************
  * Functions to prevent too many successive authentication failures.
  * FIXME: This should be performed separately per each client IP.
  */
                                                                                       
/* Maximum authentication failures before blocking connections */
#define MAX_AUTH_TRIES 5
                                                                                       
/* Delay in ms, doubles for each failure over MAX_AUTH_TRIES */
#define AUTH_TOO_MANY_BASE_DELAY 10 * 1000
                                                                                       
static int rfbAuthTries = 0;
static Bool rfbAuthTooManyTries = FALSE;
static OsTimerPtr timer = NULL;

Regards
Anton


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