A server stack is the collection of software that forms the operational infrastructure on a given machine. In a computing context, a stack is an ordered pile. A server stack is one type of solution stack — an ordered selection of software that makes it possible to complete a particular task. Like in this post about Windows Server 2016 DHCP Issue (Reserved IPs, Static & DHCP) was one problem in server stack that need for a solution. Below are some tips in manage your windows server when you find problem about windows, dhcp, windows-server-2016, vlan, .
I’ve got a problem thats driving me nuts now.
I’ve got my DHCP server set up to provide addresses over a number of different VLANs.
On the main Processing VLAN the lease time is set to 15 mins, after which all devices keep dropping off for a few seconds and reconnecting. I was under the impression that if a device was still active on the network it would skip the drop out and continue using its assigned address until it was removed from the network. This is not happening and is becoming really annoying.
I have even reserved the DHCP addresses against devices to try and fix it but they still drop off for a few seconds whenever the lease expires.
The only way i’ve found is to reserve them AND set the devices to static addresses physically on them to stop it happening. I thought a DHCP reservation would suffice.
Can anyone offer any advice?
Finally, is there a best practice way to trunk all of the DHCP scopes over one NIC? I couldnt get it to play properly so i’ve had to create a separate virtual NIC on the DHCP server VM for each VLAN even though it all goes out over the same physical NIC on the VMware host.
Im losing the will to live. But i know ive messed up somewhere.
Thanks.
the lease time is set to 15 mins, after which all devices keep dropping off for a few seconds and reconnecting.
That’s not normal behavior. A standard DHCP client tries to renew a lease after half the lease time. If that fails it’ll keep retrying until the lease runs out and then fall back to some default (link-local/APIPA mostly).
You might want to check why the DHCP clients behave like that. Recheck their settings and eventually run a packet trace to find out what’s going on.
Also, you might want to consider a longer lease period. For most purposes, something between a few hours and a few days might be more useful.
lease time is so short because we process devices for resale and have thousands of unique devices every day. our processing network is a /22.
You should have a dedicated subnet with short lease period for that.
The only way i’ve found is to reserve them AND set the devices to static addresses physically on them to stop it happening. I thought a DHCP reservation would suffice.
That disables DHCP altogether and defies its purpose.
is there a best practice way to trunk all of the DHCP scopes over one NIC?
You can either connect the DHCP server to each VLAN directly or use a DHCP relay on an intermediate switch or router.
i’ve had to create a separate virtual NIC on the DHCP server VM for each VLAN
That’s the connect the DHCP server to each VLAN directly venue – should be working.
