Every day at the same time some of the computers on my 2003 server are kick out and they have to reboot to get back on the net work.

Check your Event viewer logs for what is occruing on these (some) machines at this time interval, it likely will help in rooting out the cause you're seeing. Use a tool like EventComb to look through the logs on the affected machines to determine what is going on across them.

THE ERROR IS ATEMPT WAS MADE TO COMPROMISE SECURITY

Hello, please explain "kick out" more detailed. Are the users logged off automatically or do you loose connection to shares, etc.? Make sure to use only the domain DNS servers on the NIC. Please post an unedited ipconfig /all from a problem machine and your DC/DNS server so we cam also verify some other settings.Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.

Loose connection to shares ip 192.168.1.170 Subnet 255.255.255.0 Gateway 192.168.1.254 Preferred DNS 206.141.193.55 Alternate DNS 66.73.20.40

As per this error which kills SMB shares at the same time daily, a few questions: Is this server using VPN connections? Do you have any scheduled services, or applications which run prior or during this time which could cause this or at all look related? What is the scope of the issue? e.g can other machines (maybe different versions?) connect to the shares, while some cannot? Can machines on a certain subnet connect while others cannot?

Hello, i assume you have a domain as you didn't contradict to my first answer. Then reconfigure the client and also the DC that it looks this on the NIC: ip 192.168.1.170 Subnet 255.255.255.0 Gateway 192.168.1.254 Preferred DNS 192.168.1.(ip address domain DC/DNS server) Alternate DNS 192.168.1.(ip address 2nd domain DC/DNS server or empty) On the DC: ip 192.168.1.(ip address domain DC/DNS server) Subnet 255.255.255.0 Gateway 192.168.1.254 Preferred DNS 192.168.1.(ip address domain DC/DNS server) Alternate DNS 192.168.1.(ip address 2nd domain DC/DNS server or empty) Then configure the FORWARDERS in the DNS server properties in the DNS management console on the DC with the above mentioned external DNS servers 206.141.193.55 and 66.73.20.40. If the FORWARDERS are greyed out, delete the root "." zone in the DNS management console and restart the console. After the change of the ip address on the DC remove all external ip addresses from the DNS zones and run ipconfig /flushdns and ipconfig /registerdns and restart the netlogon service or reboot. On the client ipconfig /flushdns and ipconfig /registerdns will be enough.Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.

Thank You