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DHCP Static reservations not respected

DHCP Static reservations not respected
DHCP Static reservations not respected
2025-03-03 12:19:13 - last edited Monday
Tags: #VLAN & Multi-Networks #DHCP Service #Controller
Model: ER707-M2  
Hardware Version: V1
Firmware Version: 1.2.3

The issue I reported a few months ago suddenly returned: https://community.tp-link.com/en/business/forum/topic/711542

 

I have a bunch of DHCP reservations, but they are no longer being respected. From the log file:

 

  Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.40.17 for the client[MAC: 44-bb-3b-XX-XX-6b].
Mar 03, 2025 01:07:43 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.40.16 for the client[MAC: 44-bb-3b-XX-XX-3c].
Mar 03, 2025 01:06:43 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.40.12 for the client[MAC: 44-bb-3b-XX-XX-37].
Mar 03, 2025 01:05:42 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.50.19 for the client[MAC: 10-2c-b1-XX-XX-bf].
Mar 03, 2025 01:05:23 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.40.18 for the client[MAC: 44-bb-3b-XX-XX-f1].
Mar 03, 2025 01:04:43 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.50.18 for the client[MAC: 8c-85-80-XX-XX-52].
Mar 03, 2025 01:04:43 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.50.16 for the client[MAC: 06-17-b6-XX-XX-b6].
Mar 03, 2025 01:04:39 pm
Gateway DHCP Server Module Information
DHCP Server allocated IP address 192.168.50.13 for the client[MAC: 8c-85-80-XX-XX-5b].
Mar 03, 2025 01:04:36 pm

 

From the DHCP Reservations page:

 

8c-85-80-XX-XX-5b: 192.168.50.13 (this one is OK)

06-17-b6-XX-XX-b6: 192.168.50.11 (but got .16 instead)

8c-85-80-XX-XX-52: 192.168.50.12 (but got .18 instead)

44-bb-3b-XX-XX-f1: 192.168.40.33 (but got .18 instead)

10-2c-b1-XX-XX-bf: 192.168.50.15 (but got .19 instead)

44-bb-3b-XX-XX-37: 192.168.40.30 (but got .12 instead)

44-bb-3b-XX-XX-3c: 192.168.40.31 (but got .16 instead)

44-bb-3b-XX-XX-6b: 192.168.40.32  (but got .17 instead)

 

Obviously, this messes with my entire network as some of these are VideoSecurity or IOT devices that require a static IP addresses to be access from different VLANs.

 

Rebooting these devices or rebooting the switch or access point to which they are connected does NOT resolve the issue. The only thing that sometimes works is rebooting the router.

There are no error messages in the log. The router is for some reason completely ignoring the DHCP Reservations I've made, across multiple VLANs, and just hands out random DHCP addresses instead.

 

Router firmware is v1.2.3. Controller software is 5.15.8.2 running on a Linux host.

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#1
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1 Accepted Solution
Re:DHCP Static reservations not respected-Solution
Monday - last edited Monday

Hi @Matva 

Thanks for posting in our business forum.

Matva wrote

  @Clive_A 

 

No recent changes that I can think of. I consider my networking setup to be pretty stable. The host machine on which the controller runs reboots for updates sometimes, and whenever there is a controller update I install that.

 

For the time being, changeing he DHCP Dynamic range from .50 to .100 and keeping all DHCP Statics below .50 seems to have fixed it for now. I could try changing to back to the old configuration and see if I can reproduce it. But as mentioned, it happens *sometimes* with no way of reliably reproducing it.

707-M2 got a known bug with the DHCP service. That'll be fixed in the future. FYI.

And more discussion in Omada ER7412-M2 Firmware Updates

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#13
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11 Reply
Re:DHCP Static reservations not respected
2025-03-03 12:27:01

Settings for my VLAN 50:

 

Gateway IP 192.168.50.1
Network IP range 192.168.50.1 - 192.168.50.254
DHCP goes from .11 to .254.
 
I would like to use, for example the range .11 to .50 for static addresses and then anything above .50 for DHCP but it's not possible to create a DHCP Reservation outside of the DHCP range (which makes sense of course).
 
Or at least, that used to not be possible but now it seems it is? I'll do that and do some tests.
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#2
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Re:DHCP Static reservations not respected
2025-03-04 01:36:05

Hi @Matva 

Thanks for posting in our business forum.

How did you resolve it last time?

Did you reply to the email I sent to you? I recalled I created around 10 mails and 2-3 replies and did not follow up later on.

Others did not reply at all.

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#3
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Re:DHCP Static reservations not respected
2025-03-04 06:25:59

 Hi @Clive_A 

 

Last time it got resolved automagically by rebooting the router and all my devices. The issue didn't pop up for a while but it did again yesterday.

I don't think I received an e-mail directly from anyone at TP-Link though. But I'd happy to share my log files if that helps in troubleshooting the issue.

 

Best regards

 

 

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#4
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Re:DHCP Static reservations not respected
2025-03-04 07:01:45 - last edited 2025-03-04 07:03:39

Hi @Matva 

Thanks for posting in our business forum.

Matva wrote

 Hi @Clive_A 

 

Last time it got resolved automagically by rebooting the router and all my devices. The issue didn't pop up for a while but it did again yesterday.

I don't think I received an e-mail directly from anyone at TP-Link though. But I'd happy to share my log files if that helps in troubleshooting the issue.

 

Best regards

 

 

I created emails for others in your previous thread. They replied after you posted your solution and stated that your issue was resolved by itself.

 

You can send your file and log to the email:

Since the beginning of 2025, we no longer create the email ticket for the user. To assist and figure it out efficiently, we recommend submitting a support ticket via email.
Please include:
1. Your Forum ID;
2. Your community nickname;
3. A detailed description of the issue and result if I have suggested anything on the thread, and the troubleshooting steps you've taken in the subject line or body of your email.

 

It would be great to include a diagram of your network with IP specified. Log is not really what we are after.

If possible, you can export your backup and paste it in the email.

What did you do recently? Any modifications? Upgrade anything from what version to what version.

Does this behavior happen to the wired clients?

What you observe on the client network interface and the log, pick one and illustrate. If possible, you can use Wireshark and capture the wrong IP assignment from the router.

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#5
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Re:DHCP Static reservations not respected
2025-03-04 07:20:43

  @Clive_A 

 

I've sent an email with some information and will see if I can upload a full backup file and a network drawing as well.

Wireshark will be difficult, as these are mainly IOT and Videosecurity devices with no means of opening an interactive shell. Most are wireless, but one or two are wired.

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#6
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Re:DHCP Static reservations not respected
2025-03-04 07:23:56

Hi @Matva 

Thanks for posting in our business forum.

Matva wrote

  @Clive_A 

 

I've sent an email with some information and will see if I can upload a full backup file and a network drawing as well.

Wireshark will be difficult, as these are mainly IOT and Videosecurity devices with no means of opening an interactive shell. Most are wireless, but one or two are wired.

That is to say that both wired and wireless experience the same issue with the DHCP.

Does it happen after the reboot? With the very first DHCP interaction, it will send the wrong IP assignment to the wired/wireless clients?

If so, disconnect the cable, and you can configure the Port Mirroring, perform a reboot. And the computer is connected to capture, connect the wired client to it and see how they interact in the DHCP.

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#7
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Re:DHCP Static reservations not respected
2025-03-04 15:40:51

  @Clive_A I would also like to add I have the exact same issue. Same router, same firmware and controller version. I just set up the network and have been running it for a few days so I am fairly new to it all, but if there is anything you need from me or info I can provide, please let me know. I would like to get this resolved as well.

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#8
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Re:DHCP Static reservations not respected
2025-03-05 01:01:46 - last edited 2025-03-05 01:02:43

Hi @Yarzy 

Thanks for posting in our business forum.

Yarzy wrote

  @Clive_A I would also like to add I have the exact same issue. Same router, same firmware and controller version. I just set up the network and have been running it for a few days so I am fairly new to it all, but if there is anything you need from me or info I can provide, please let me know. I would like to get this resolved as well.

Werid.

In the last report wave, around 10 people reported similar issues and all disappeared within a week or so. I created like 10 tickets for them. They don't really follow up and provide details on this matter. And I closed them after waiting for a reply for 3 months. 

And none reported in the last 3 or 4 months. Zero report on DHCP.

 

And now it looks like another wave.

In the last 3 months, recently when you notice there is an issue with the wrong IP, what did you upgrade? What changes made on your system?

 

Do the steps I have written above. What are the results in each step?

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#9
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Re:DHCP Static reservations not respected
2025-03-05 05:42:13 - last edited 2025-03-05 05:47:32

Hi @Matva 

Thanks for posting in our business forum.

Matva wrote

  @Clive_A 

 

I've sent an email with some information and will see if I can upload a full backup file and a network drawing as well.

Wireshark will be difficult, as these are mainly IOT and Videosecurity devices with no means of opening an interactive shell. Most are wireless, but one or two are wired.

Did you make any changes recently? I asked in the earlier replies. It was not answered.

Before what you described, changing the subnet from starting with 50.2 to 50.100, if you reboot, will it work properly again?

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#10
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Re:DHCP Static reservations not respected
2025-03-05 07:40:34

  @Clive_A 

 

No recent changes that I can think of. I consider my networking setup to be pretty stable. The host machine on which the controller runs reboots for updates sometimes, and whenever there is a controller update I install that.

 

For the time being, changeing he DHCP Dynamic range from .50 to .100 and keeping all DHCP Statics below .50 seems to have fixed it for now. I could try changing to back to the old configuration and see if I can reproduce it. But as mentioned, it happens *sometimes* with no way of reliably reproducing it.

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#12
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