DHCP Reservations not working

Networking & Firewalls
1

I have a Dell server that has a reserved IP address in a VLAN reserved for cameras. The cameras are still getting IP addresses in that VLAN, but for reasons which I have yet to figure out, the server is getting an IP in my corporate VLAN. Nothing has changed with the server config, and I’ve restarted the DHCP server, the SG7100-1U, and the Dell Server, all to no avail. I am stumped as to why the server is getting an IP in the wrong VLAN, but all the cameras still get IPs in the Camera VLAN. Any suggestions would be greatly appreciated.

2

If Dell server is linux, look at /etc/network/interfaces

3

It’s windows, but thanks for the suggestion!

4

Hey razimak -

Based on your description, here’s the things that run through my mind (on the first pass, anyway) that could contribute. Based on my name, you can probably guess that I look at things more from a network perspective, so apologies in advance for that bias:

  1. Any network topology changes? I’ve seen a random unmanaged switch plugged into a tagged port cause all kinds of weird issues. I personally want to Office Space small unmanaged switches that I randomly find in my network. If it’s not managed I don’t want it on my network.
  2. Are there any config changes to the switch port facing the server in question?
  3. Speaking of the switch port, is it tagged, untagged, or does it have a native VLAN assignment?
  4. Is there (or should there be) tagging configured on your server’s NIC?
  5. Is the server a VM? Has anything changed on the virtual switch config?
  6. Do you have anything like Cisco’s VTP in your environment? I wouldn’t expect that to cause issues at the port level unless a vlan no longer becomes available to a switch and the port defaults back to native VLAN.

I know I’m answering your question with questions (frustrating!) but troubleshooting is all about finding the right question to ask.

Good luck, and if you find the answer, please post back, you have my curiosity up. :smiley:

5

Hey PacketFrack,

Thanks for your suggestions. All of my switches are managed switches, and I do have lots of ports tagged, and I’ve just been doing some rewiring on my network, so before I even go check, I’m going to say you gave me the thing I was overlooking… most likely I got a port or 2 crossed, so I’m going to go have a look at that, and I’ll let you know if that, or any other of your suggestions did the trick!
Thanks again!

1 Like
6

Yep, that was it! In the course of rewiring my rack, I managed to plug the camera server into a port that wasn’t configured for that VLAN. I’m most disappointed that wasn’t the very first thing I thought to check.

Thanks again, for reminding me what I should have known to do, but obviously didn’t!

Best regards!

7

Any time at all. At any given point there’s like 1,000 things going through our heads when things aren’t behaving, so not remembering one specifically isn’t surprising. Give yourself a break, luckily this one had an easy button. :wink: