IP Address Issue

[Andie]

We are trialling AB Tutor Control, and it has thrown up something on our network that I need help from you experts on!

 

When we watch computers using AB, it shows one person as being logged onto three machines. We have physically checked who is logged on at the actual machines and this is incorrect. Same three machines each time. So I've been checking IP addresses. If I physically go to each machine and do ipconfig I get three different IP addresses. However, if I do ipconfig using cmd prompt from AB Tutor I get all the same IP address.

 

So I've had a look at DNS and DHCP. These both run on the same server. And the same problem IP address is in DNS for all three machines in forward lookup, although the machines themselves think they all have different IP addresses. Reverse lookup seems to be a mess, with multiple records for some machines and missing records for others.

 

In DHCP, the address leases shows different IP addresses for the three machines that are giving the problem.

 

I think there is some breakdown of synchronisation between these programs, but don't know where to start to fix this. I guess the first thing would be to sort out the duplication of IP addresses in DNS forward lookup? How please? (In easy to follow steps!!!)

[Geoff]

Enable scavanging in DNS. That should tidy up your reverse lookup zone.

 

I'm confused by what you say about the machines having three IPs. Do they have three network cards then?

[ricki]

HI

 

Once you have fixed dns you might also need to log on to abtutor as a administrator and it will search for all the machine and update the records. This does not rely on dns but searches the domain address range as far as I know.

 

Richard

[Andie]

Enable scavanging in DNS. That should tidy up your reverse lookup zone.

 

I'm confused by what you say about the machines having three IPs. Do they have three network cards then?

 

Sorry, I meant that three different machines all had the same IP address in DNS forward lookup. Not if you look in DHCP leasing, and not if you go to the machines themselves.

 

How do I enable scavenging? Will this fix the problem of three clients with the same IP address in forward lookup?

[Andie]

HI

 

This does not rely on dns but searches the domain address range as far as I know.

 

Richard

 

That's what I thought too, looking at the help stuff for ABT, but then why are we getting this problem in AB where it shows the same IP address for three different machines? In Watch mode, this means that one machine screen and the associated login is shown in three different places.

[Geoff]

http://blogs.technet.com/networking/archive/2008/03/19/don-t-be-afraid-of-dns-scavenging-just-be-patient.aspx

[Andie]

Thanks. I will read, and hopefully learn!

[Andie]

I've been reading through the scavenging article, and looking at what is already set here. No scavenging is enabled yet on zone or server. But when I go to the Resource Record in DNS, I compare the properties to the screenshot on the article, and we don't have the box ticked next to "Update associated PTR record". Is this a problem?

 

Whilst I tackle the issue of scavenging, I have been looking at the tools in ipconfig. I've tried to do ipconfig /renew on one machine, but it still comes up with the same ip address. Also there is a /registerdns setting - can someone tell me if that will send ip address info back to DNS and update things manually. I could maybe use this on the two machines that AB Tutor thinks have the same ip address as a third machine.

 

I still don't really understand how DNS is apparently affecting AB Tutor, as it says it doesn't use DNS...??