I had difficulties with our network speed, we still had 100MBit switches so we made a change and replaced our 3 switches with some nice new ones (1 central 16 port going to 2 switches with 24 ports). I have decided to buy the HP 1920-16G and HP 1920-24G. Right now we plugged the switches in and things worked out of the box. We have 2 servers, one being the Domain Controller (Name: Alpha, IP: and the SQL Server (Name: Delta, IP:

Even though the computers are reached and my Domain Controller gives the users the DHCP lease the network is not recognized as a domain network anymore.

In Network and sharing this used to be displayed (Domain Controller still has it):

enter image description here

Now it is some unidentified network:

enter image description here

The users can log in but they can not automatically log onto network shares. Also authentication in the SQL (Windows authentication) does not work anymore and/or users can not change their user passwords by hitting ctrl+alt+del and select "change password".

This all makes me believe that either something in the mananaged switches is limiting a protocol of the domain controller or that during my reboot of the domain controller (changed things in the patch panel and had to disconnect power of server) some services where not started?

I am quite stranded here having 20 people unable to work properly right now, any Ideas?

  • 1
    Have you looked if the network connection is stable (using netio.exe UDP test between one client and the server) how high is the packet loss? You may need to shutdown firewalls for that test. – marsh-wiggle Dec 3 '14 at 7:45
  • Pinging with 65500 bytes is responding under 1ms, never any packages lost. NetIo -u alpha gives me back that the speed of 1k bytes packets is 86,3 MByte/s and of 32k byte packages 57.8 MByte/s. – Dominik Dec 3 '14 at 8:11
  • So, 0% packet loss to both alpha and delta. No firewalls shutdown for this. – Dominik Dec 3 '14 at 8:28
  • can you temporarily got back to the old swithes? – marsh-wiggle Dec 3 '14 at 10:19
  • What are the clients using for DNS? What is the DC using for DNS? Have you checked the AD related services on the DC to see if they're started? Have you checked the Event logs on the DC? Start troubleshooting by checking the basics. – joeqwerty Dec 3 '14 at 15:16

Where are the DCs connected - one on each switch, or both on one switch? Where are clients connected? Wondering about how traffic is getting across those switches - trunk/bridge or routed?

  • The Windows 8 clients don't work no matter how they are integrated in the network. I have a central switch with the DC and a SQL server. From there are two other switches that have most of the clients. Why are only win 8 clients affected? – Dominik Dec 7 '14 at 10:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.