DHCP Limit Help / dnsmasq

[LighthammerX]

Greetings,

I'm running an ASUS AC-3100 with the current Asuswrt-Merlin firmware.

I'd like to be able to up the DHCP Limit probably up to the maximum. I keep a pretty firm grip on my IP assignments and I know the scope of what I do is probably FAR outside what the average user is going to need/do, so making a request to increase the DHCP limit is probably silly (though, I could probably live with the limit being doubled from 64 to 128).

A primary reason for my need is the fact I've added *A LOT* of smart devices to my home. I've probably doubled my IP assignment needs from this alone. I've moved things like Lightbulbs to the DHCP, but being the control freak I am when it comes to network management, I don't really like this setup. I still prefer being able to look at a given light and know where it is on my network.

In doing some research on this forum, it looks like doing a dnsmasq might be best for my usecase, but I'm not seeing a good walkthrough how to do this (this is new territory for me).

I wanted to see if someone could point me in the right direction of how to either increase the DHCP limit myself or to setup and manager a dnsmasq.

Thanks in advance.

 

[eibgrad]

When you create a static lease in the GUI, all the router does is create a dhcp-host record in the underlying DNSMasq config file, which you can readily dump w/ the following command using SSH.

grep dhcp-host= /tmp/etc/dnsmasq.conf

Just use that as a model for creating your own dhcp-host records and adding them via a DNSMasq custom config file.

And btw, while I understand the need to know about these IOT devices, there's no need to assign them static leases (at least not all of them). You can simply create dhcp-host records that *only* specify the hostname and MAC address, w/o the need for a specific IP assignment. The device just grabs an IP from the DHCP pool, but it still shows up on most device lists since it has a dhcp-host record. I just can't see creating a static lease for a device that has no addressable interface by which you can access it.

 

[eusagc]

If you have amtm/entware running, you can also try installing the YazDHCP addon. On my AC88U at least, the static assignment has been increased from 64 (default) to 162 (dunno how/where this limit is set). It also lets you import/export CSV lists, very convenient if you've got a lot of static stuff.

And btw, while I understand the need to know about these IOT devices, there's no need to assign them static leases (at least not all of them). (SNIP) I just can't see creating a static lease for a device that has no addressable interface by which you can access it.

Word! In my case, I put all my IoT stuff into a guest SSID, and assign a DHCP pool range for this. I don't care what IPs they get, since, as eibgrad above, they got no access interface anyway. Exceptions for me are IP cams, because of ONVIF/RTSP.

 

[Jack Yaz]

If you have amtm/entware running, you can also try installing the YazDHCP addon. On my AC88U at least, the static assignment has been increased from 64 (default) to 162 (dunno how/where this limit is set). It also lets you import/export CSV lists, very convenient if you've got a lot of static stuff.

It's calculated using 6kb (to stay below addon api save limit) divided by the average length of your reservations. A greater number of reservations is also possible by chopping out the subnet when saving (i.e. A /24 is assumed and only the final octet is passed via the api)

 

[eusagc]

A greater number of reservations is also possible by chopping out the subnet when saving (i.e. A /24 is assumed and only the final octet is passed via the api)

Thanks for this info. I'll do it like this in my static list.

 

[LighthammerX]

It's calculated using 6kb (to stay below addon api save limit) divided by the average length of your reservations. A greater number of reservations is also possible by chopping out the subnet when saving (i.e. A /24 is assumed and only the final octet is passed via the api)

Thats an interesting factoid.

Thanks for the guidance all, especially from eibgrad.