Weird WINS/DNS issue

[gerardsweeney]

Hello, all..

 

Caveat here - I'm not an Infrastructure person. I'm primarily desktop.

So any laughably poor explanations abobut the comms setup are down to that

 

 

 

I'm having an issue in at least one of my schools. It may be happening elsewhere,

but the nature of the issue means it's difficult to pin down.

 

In a nutshell - I have workstations which seem to be losing their WINS/DNS registration FAR too quickly.

 

To describe the symptoms, I'll use an example of a made-up workstation called OFFICEPC01 with a made-up IP address of 10.11.12.13

 

 

MONDAY 11am - OFFICEPC01 powered up

From my (or any) workstation located in the school, I can open CMD

and PING OFFICEPC01 and I'll get a reply from 10.11.12.13.

I can connect to OFFICEPC01's ADMIN$, look at the registry, files on C: from the comfort of my workstation.

 

 

MONDAY 2pm - OFFICEPC01 switched off

From my (or any) workstation located in the school, I open CMD

and PING OFFICEPC01. I get a request timed out from 10.11.12.13

Pretty much what you'd expect.

 

 

TUESDAY 11am - OFFICEPC01 still powered off

OFFICEPC01 has been switched off since yesterday.

 

From my (or any) workstation located in the school, I open CMD

and PING OFFICEPC01. I get "Unknown host".

In other words, the WINS/DNS resolution is gone.

 

 

If I power OFFICEPC01 back up, then it's business as normal.

 

 

This loss of WINS/DNS isn't happening to all PCs, but it IS happening.

I can reproduce this with an ICT suite - power them all up on Monday.

It's pretty much guaranteed that if I try to PING all 21 on Tuesday,

at least 5 will return Unknown host.

 

Weirdly, I can take this to the other extreme - I can have a PC powered off for

weeks (during the Summer break, like now), and WINS/DNS will still resolve its name.

 

 

I should say that PINGing the FQDN doesn't produce any different results.

PING OFFICEPC01.school.authority still produces the Unknown host.

 

 

 

In terms of our setup, we have 2 DHCP servers - both living in our DC.

I believe(!) that 1 is the main DHCP for one half of the authority, while the other

is the main DHCP for the other half. I believe(!) that should DHCP1 fail, DHCP2 is

meant to kick in.. I'm not 100% certain on that, but I can confirm if need be.

 

In terms of WINS, we have 2 - WINS1 and WINS2. WINS1 lives in a High School (the one I'm in) and is the primary

WINS for half the authority. WINS2 is in the DC and is the secondary for that half of the

authority. These 2 roles are mirrored for the other half of the authority (as in WINS2=Primary, WINS1=Secondary)

 

In terms of DNS, we have 8. One per High School and one in the DC.

Each High school and its linked Primary have the High School DNS as the primary DNS, and the DC one as the secondary.

 

All workstations and their IPs are setup using DHCP. We don't use statics for anything except servers.

Which live on a different VLAN from the workstations.

 

The worksations can have 1 of 2 different VLANs assigned to them - Admin or Curricular.

 

The host name loss issue described above happens to workstations on either.

 

 

 

I don't know if that's enough information - please shout loudly if you need anything else.

 

 

Cheers,

Gerard

[MordyT]

Sounds normal to be honest. Would need more info, such as DHCP lease time, if DHCP is authorized to add and remove records from DNS, DNS scavenging setup, etc. Its the PC that is off for weeks still having a record that worries me instead. But possible to explain if you have different configs on each DHCP server.