DHCP Server

[DSAGEY]

Hello,

 

After facing many issues with our iPads and Chromebooks unable to locate the DHCP server, I have decided to give them a Static IP.

 

I have noticed on the DHCP server, that not all the IP addresses from our rang appear, so I'm unable to add a reservation. Has nyone got any suggestions as to why not all addresses from the IP range don't appear? I have the Start IP and End IP setup with some addresses excluded.

 

Thank you

[HPlum78]

So sometimes when networks are setup they will exclude parts of the range for network hardware and such likes or / down the allocation. Give us an idea of the range? Also I would suggest root causing the issue with DHCP rather than moving to a static allocation (that way madness lies!) happy to help where I can. Edited January 20, 2021 by HPlum78

[DSAGEY]

So sometimes when networks are setup they will exclude parts of the range for network hardware and such likes or / down the allocation. Give us an idea of the range? Also I would suggest root causing the issue with DHCP rather than moving to a static allocation (that way madness lies!) happy to help where I can.

Here is a bit of background on our IP Range;

 

Our range originally up until December 2020 was 10.41.90.0/24 this was increased due to having issues with connecting to the WiFi but overall we had no issues with devoces disconnecting.

 

Since the IP range changed, we are now 10.41.88.0/21 since then we have had issues with iPads/Chromebooks connecting to the DHCP, our server support company made the necessary changes to the DNS/DHCP.

 

I'm not sure if you've heard of Ergo Free2Teach software? But I have noticed that any devices that fall outside of our old IP range I get a message saying "Unable to locate server" but when I have a device that receives an old IP of 10.41.90 then it works, where if it has 10.41.88, 10.41.87, 10.41.89, 10.41.91, 10.41.92, 10.41.93, 10.41.94 or 10.41.95 I can't the error message.

 

Thank you

[FN-GM]

You need to segment your network. It’s not a good idea to have a /21 for genera traffic.

 

Do you have layer 3 switches? Were the changes made on these? Was the change to the subnet mask made on the server?

[DSAGEY]

You need to segment your network. It’s not a good idea to have a /21 for genera traffic.

 

Do you have layer 3 switches? Were the changes made on these? Was the change to the subnet mask made on the server?

 

I don't personally get involved with the networking side of things like the DNS or DHCP all I do is reserve an IP address if required, for example our door system.

 

Yes the changes were made on the layer 3 switches and the subnet mask was changed on the server.

[TwistedHelixis]

I also did something very similar a few months back.

 

I know you probably have done this but did you remember to reconfigured your WiFi controller with the new range? And depending on your WiFi setup did those setting propagate properly to all access points?

[Davit2005]

I don't personally get involved with the networking side of things like the DNS or DHCP all I do is reserve an IP address if required, for example our door system.

 

Yes the changes were made on the layer 3 switches and the subnet mask was changed on the server.

 

Was the DHCP scope updated on the server?

 

One thing I have seen before was infinite leases, these can cause issues and I would not recommend, a reservation is far better if you do need something on a fixed IP. Even if you have something static, for instance I've seen HP printers go back to DHCP before now for no apparent reason.

Edited January 21, 2021 by Davit2005