Windows Server 2008 DHCP: Lease offered, but not accepted

My Windows Server 2008 should be configured to work as a DHCP Server in the Network. Therefore I setup the Role and configured everything.

I have downloaded a tiny tool, that can show DHCP-Offers on the Network. When executing it, i receive:

Packet from 192.168.100.5 
 Offered IP 192.168.100.202 
 Subnet Mask 255.255.255.0
 Renew Due in 345600 Seconds
 Lease Length 691200 Seconds
-------------------------

So this seems to work fine. However if I setup my network card to receive an IP from DHCP, it simple does not receive anything. Windows (Client) then picks up its default "No-DHCP-Available" Adress like "169.254.21.222 (Preferred)"

Service is Running, IPs are "offered", Also Login-Data for Dynamic DNS Update (DHCP == DC) is configured.

Windows Server Logs show nothing. Any Idea how I could debug this best?

edit: The DHCP is authorized on the Domain as well.

UPDATE 1: Wireshark:

I downloaded Wireshark for the Server and for the Client. Started it, and tried to /release, /renew IP-Adress... Nothing was logged (used filter (bootp.option.type == 53)) - Neither on Server, nor on Client side.

So, I disabled DHCP on my Server, re-enabled it on my dedicated router (Fritz Box), rebooted the client, and finally could trace a request done by the client:

8328    7.052393000 192.168.100.29  192.168.100.2   DHCP    362 DHCP Request  - Transaction ID 0x51a0cafa
8329    7.054365000 192.168.100.2   192.168.100.29  DHCP    590 DHCP ACK      - Transaction ID 0x51a0cafa

So, the client seems to work well in terms of DHCP.

I Enabled DHCP on the Server again, and set up the client to use a dynamic IP, but using the DNS of my Server as the primary (and only) DNS-Server. Again, I get nothing. (And again no Wireshark Logs on any device)

I noticed, that when doing /release, /renew, the /renew always throws an error, when having the DHCP on the Server enabled. (An attempt was made to access a socket in a way forbidden by its access permissions.)

But this looks like a local error to me, not sure what it has to do with the presence (or absence) of any DHCP Server.

UPDATE 2: I now did the following: Using a Static IP Adress, I started Wireshark on the Server, and switched to a Automatic Configuration on the Client. It didn't receive a IP-Adress (using the default of 169.254.21.222. Again, no Wireshark logs on the server.

Then I used the same configuration, and used the DHCP-Finder-Tool. Now the Server logged several DHCP Discovery Entries from THAT IP-Adress.

779 55.354991000    169.254.21.222  255.255.255.255 DHCP    590 DHCP Discover - Transaction ID 0x9a020000
780 55.355668000    192.168.100.5   255.255.255.255 DHCP    342 DHCP Offer    - Transaction ID 0x9a020000

However the client did NOT receive a IP Adress. Also the tool did not show any response, as it does, when using it from a hardcoded IP-Adress from within the same subnet.

UPDATE 3: Now I am Confused: Just checked the Adressleases of the DHCP and noted, that ANY WLAN-Device out there has successfully leased an IP Adress. (Duration ~ 8days)

However, for my (wired) Clients it still fails... ?

https://abload.de/img/wifi1b3xf7.png

Wlan Clients are connected through an AccessPoint, that is connected to the very same 24-port switch every wired client is...

Just connected my PC with a spare WLAN-USB-Dongle - Worked perfectly fine...

https://abload.de/img/wifi23ojcg.png

ps.: I am very very familar with server setups - but this blows my mind - Why would there be a distinction between WLAN and WIRED clients, when it comes down to DHCP ?!

After Rebooting (and multiple times en/disabling) the client('s network connection) it works...

Maybe there is a "Cache" layer, that delayes the access on "new" DHCP Servers... However, so far my local client is the only one out of 20 that has successfully requested an ip-adress... i'll leave it like that and check the status tomorrow.