AB Tutor V6.1 client identification problem

[a-worton]

I have a problem with AB Tutor V6.1

I have a lab with 20 machines. machine 19 has the control software installed as well as the client.

Machine 2 in the room is detected and works along with all other machines fine when I search for <ALL> on startup.

I have added all machines in this room to a group called lab-2 so that teachers get access only to that room when using abtutor.

When the machines are accessed using the group (either as tutor or admin), ABTutor control identifies machine 2 and connects to it, but it actually connects and reports a different machine in another part of the building (classroom machine 7).

Both classroom machine 7 and lab2 machine 2 are accessed properly and work when <ALL> computers are searched.

Whenever Lab2 machine 2 is included in any group (including a group on its own) it always connects to classroom 7 machine.

THe affected machines use DHCP to get an ip from Active Directory DC and they have different hostnames.

What could cause this? Any help appreciated.

[Andy]

This is definitely a problem with your DNS/DHCP servers not synchronising correctly.

The following article explains in detail the differences in the 2 methods of Finding and connecting to machines.

http://www.abconsulting.com/ActiveKB/questions/20/Sometimes+ABTC+seems+to+allocate+names+to+machines+at+random

Basically, the '<All>' group sends out a broadcast message on the network that is picked up by any running clients. Each client then sends back its current IP address to the tutor and so the tutor can make a direct connection back to that IP. If you select a group of machines, then the Tutor program asks your DNS server to resolve the computer name to an IP address via your DHCP server. It then assumes that the IP address is correct and tries to connect to that IP.

If your DNS server fails to resolve the computer name, then you will get an 'Unable to resolve host' error. If your DNS server returns an IP address that actually points to a different machine under DHCP, then you will either connect to the wrong machine or possibly get an 10060 or 10061 error as it tries to connect to a machine that does not have the ABClient installed. If you have different Connection Passwords setup in different classroom groups, then as it tries to connect to a machine in a different room you will get an 'Invalid Connection Password' error.

You must make sure that your DNS and DHCP servers synchronise at the same time to avoid these problems.