PCs dropping off the network

[SpuffMonkey]

We've had a problem over the last couple of weeks - with PCs at the login screen that cannot "see" the network. Rebooting solves it. The only changes that I've made were some of the changes recommended in the scavenge DNS thread that was being discussed on here. I have set all the settings back to what they were before (I think) - any ideas??

[RobC]

We get this here a lot. User attempts to log in & gets the message "The Domain ELGINC is not available." Rebooting the system solves it. I've never actually pinpointed what causes it, but I have found that when this happens, the link light on the network port has gone out.

For info, we are using ADMtek AN983 onboard network adaptors in our systems which are Fujitsu-Siemens Scenic P300's. The switches are Cisco Catalyst 1900 series running at 10Mbit/s.

[ChrisH]

This kind of thing is usually DNS/DHCP related. I had this problem recently because of our proxy that decided to turn DHCP on even though it didnt have any scopes configured and the clients always found that one first :?
Check the logs to see if theres any strange activity reported.

[marco84]

Had a similar problem here, but since then we have re-built both DHCP and DNS. The problem dosent seem to exist anymore.

[DMcCoy]

We've had a problem over the last couple of weeks - with PCs at the login screen that cannot "see" the network. Rebooting solves it. The only changes that I've made were some of the changes recommended in the scavenge DNS thread that was being discussed on here. I have set all the settings back to what they were before (I think) - any ideas??

I don't think scavenging itself would cause an issue as it only removes dns entries that have expired. Static entries and aliases are not removed. Are there any relevant errors in the event logs on the clients for the times they fail?

When they do fail, I suggest you log on locally and run an ipconfig to see if it has acquired a valid address. Check the dns servers are set correctly in the scope and that there are enough free dhcp addresses.

[SpuffMonkey]

OK - any pointers to an idiot's guide to trouble shooting DNS/DHCP??

[Dos_Box]

Check all of your name servers are present on all of your DC's DNS settings.

Ensure that replication is enabled.

Make sure the forwarders are your 'upstream' DNS servers, not your internal ones.

Check that the only DNS servers listed on the TCP\IP properties on your DNS server is it's own address. The DNS service takes care of all replication and lookups. You don't want your DNS servers looking anywhere than themselves.

Check that DHCP is giving out your name servers under the DNS settings, and not your upstream DNS.

[_Bob_]

Spuff monkey, install the Support Tools and run netdiag and dcdiag. These often point in the right direction for DNS issues.

RobC - It's strange that the link light goes out as this just indicates a physical connection. I'd check for any power saving tools associated with the network card. I came across one installed on a laptop which turned off the NIC after 15mins of inactivity. The only way to get the NIC back on was to reboot. (Who comes up with these things!)

[Geoff]

I came across one installed on a laptop which turned off the NIC after 15mins of inactivity. The only way to get the NIC back on was to reboot.

Ahahahah, that was a toshiba wasn't it.

[SpuffMonkey]

Check all of your name servers are present on all of your DC's DNS settings.

Ensure that replication is enabled.

Make sure the forwarders are your 'upstream' DNS servers, not your internal ones.

Check that the only DNS servers listed on the TCP\IP properties on your DNS server is it's own address. The DNS service takes care of all replication and lookups. You don't want your DNS servers looking anywhere than themselves.

Check that DHCP is giving out your name servers under the DNS settings, and not your upstream DNS.

Thanks for that - but alas I need it a bit more idiot than that!

[SpuffMonkey]

Check all of your name servers are present on all of your DC's DNS settings.

Ensure that replication is enabled.

Make sure the forwarders are your 'upstream' DNS servers, not your internal ones.

Check that the only DNS servers listed on the TCP\IP properties on your DNS server is it's own address. The DNS service takes care of all replication and lookups. You don't want your DNS servers looking anywhere than themselves.

Check that DHCP is giving out your name servers under the DNS settings, and not your upstream DNS.

Thanks for that - but alas I need it a bit more idiot than that!

[Dos_Box]

I've PM my telephone number to you. Ring me.