Hey everyone! I'm trying to figure out why our DHCP server is running low on available addresses for our specific scope (10.XXX.32.XXX). Here's what I've got:
- **DHCP Scope range:** 10.XXX.32.20 - 10.XXX.32.250
- **Lease Time:** 8 days
- **Statistics:** Total Addresses: 231, In Use: 213, Available: 18
The weird part is that one device, with the hostname S2209L29G.CONTOSO.DOMAIN, has been assigned 20 different IPs, but the client IDs are different. Also, I've noticed there are duplicate registrations for two Android devices, both using random MAC addresses.
Does anyone have any thoughts or potential solutions to help me out? Thanks!
4 Answers
1. Lower your lease time to around 10 hours. 2. Investigate the Android devices - they might need to be on a different VLAN to reduce the load on your DHCP server. Also, make sure DNS scavenging is properly set up to clean up stale records regularly.
Definitely check that device that's causing the address hogging. It appears to have some MAC randomization settings enabled, which is common on mobile devices for privacy reasons. Turning that off could reduce the consumption of addresses significantly.
I’ve seen similar issues with those privacy settings; they can wreak havoc on your DHCP settings if a device keeps changing its MAC address.
You might want to shorten your lease time. Eight days seems quite long, especially with so many mobile devices connecting and disconnecting. I find that a lease time of around 8 hours works better in dynamic environments. It helps free up IPs quicker, especially for devices that are not always on the network.
Totally agree! A shorter lease time can really help manage the IP allocation without disrupting things for devices that are still connected. I've been using a 2-hour lease time, and it works perfectly!
You should really consider splitting this subnet or expanding your DHCP scope. Twenty different addresses for a single device is concerning. It might just be the device’s way of handling DHCP renewals with random MACs causing this mess. Try decreasing the lease duration to 1-2 days. It should help manage IP allocation better.
Yeah, maintaining a clean DHCP table is key with all these devices. And those random MACs can really mess things up!
Exactly! Keeping mobile devices on a separate VLAN and lowering lease times can keep your network healthy!