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lately I've been having some problems with my DHCP and my clients IP.

So basically, in my netwrok I have a DHCP server (Windows 2012 R2) which is working fine (when you connect to the network you get an IP, and you have connectivity), and then I have some client machines which are static-IP configured.

The problem is that every now and then these clients lose connectivity, and when i check them out they have a 169.254.x.x IP. I know that this IP is an auto-assigned DHCP address, but I don't know why this is happening since the clients are configured to have a static IP. To fix it, I only have to restart the network adapter on the problem machine.

I'd like to know if there is a reason why this is happening and how to solve it.

bernat123
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  • What do the logs say? – Jenny D Dec 13 '17 at 10:37
  • If a windows client has a static IP defined locally, then it wouldn't show an APIPA IP, it would show the assigned IP. Are you talking about static IP reservations in your DHCP console that are not also explicitly defined on the workstation as well? – DanBig Dec 15 '17 at 15:17

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169.254.x.x IP are not IP assigned by DHCP server. It is an APIPA IP. Since clients are losing connectivity intermittently most probable cause will be a IP address conflict. To troubleshot this 1. Check for IP address conflict messages in eventlog 2. Cross check IP scope in DHCP server and client IP addresses and to see whether there is any overlapping. 3. If there is any overlapping use DHCP exclusion to remove conflicting IP range or use IP addresses which not in DHCP server for static cleints 4. Also verify that all clients are having unique static IPs.

AMT
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Are your static IPs in the same address space as allocated by the DHCP server? It's possible the interfaces are dropping back to the link local IP (169.254.x.x) due to an IP conflict - e.g. the DHCP server has allocated the IP they are using to another device.

If this is the case you'd need to add address reservations for the static IPs on the DHCP server or have the DHCP server dynamically assign the IP to the device.

DanGahan
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