YazDHCP YazDHCP - feature expansion of DHCP assignments (increasing limit on the number of DHCP reservations)

joe scian

Very Senior Member
it'll be a YazFi feature if/when i get back to coding in the near future (dog had surgery yesterday to remove a lump, could be cancer, we find out next week)

Sorry to hear that Jack - hope the prognosis is good
 

Wade Coxon

Senior Member
Can anyone tell me if there is a known speed bottleneck with the default Merlin DHCP implementation?

I am seeing a delay of about 3.5 seconds when my client request an IP address, and am wondering if yazdhcp has any optimisations to improve this?

I presume that the default DHCP is waiting on a ping response from a host prior to allocating the IP, but not sure what the default timeout is for that (surely not longer than 1s?).

I suppose I could add the no-ping option to dnsmasq.conf.add, but that might be problematic....I'd prefer to be able to adjust the timeout only. Not sure if that's possible. Maybe just worth trying as an experiment?

This delay is currently causing issues with one of my devices who's UI needs to know the IP address on startup, and DHCP is taking too long.
 

ColinTaylor

Part of the Furniture
I am seeing a delay of about 3.5 seconds when my client request an IP address, and am wondering if yazdhcp has any optimisations to improve this?

I presume that the default DHCP is waiting on a ping response from a host prior to allocating the IP, but not sure what the default timeout is for that (surely not longer than 1s?).
Looks like the delay is hard coded to 3 seconds.

https://github.com/RMerl/asuswrt-me...b/release/src/router/dnsmasq/src/config.h#L38
https://github.com/RMerl/asuswrt-me...elease/src/router/dnsmasq/src/dnsmasq.c#L2072
 

Wade Coxon

Senior Member
Ahh, thanks for that.
I thought I read somewhere that the ping test is not run if the address appears in the host list as a defined MAC/IP. Can't find reference to that, so might have been dreaming.

A bit of a shame it seems. I might have to enable the no-ping option to speed things up, but I would prefer to not have the router hand out duplicates to my DHCP devices that just grab an address from the pool (an old Billion router I had used to do this a lot).
 

ColinTaylor

Part of the Furniture
I thought I read somewhere that the ping test is not run if the address appears in the host list as a defined MAC/IP. Can't find reference to that, so might have been dreaming.
I've just tested this using Wireshark and that does appear to be the case. When I added my client to the "Manually Assigned.." list there was no ICMP and the DHCP Offer came back in < 1ms, whereas before I could see the ICMP and > 3 second delay.
 
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Hazel

Senior Member
When the next stable release of Asuswrt-Merlin comes out, I would like to start completely fresh and keep my setup as simple as possible, yet with static assigned IPs. Is there a way to restore the static IPs after resetting without the need to reinstall YazDHCP? I have exported them using the UI in the designated .csv file. I have less than 25 static IPs so I'm well within the limits that Asuswrt-Merlin provides by itself. Any suggestions?
 
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JGrana

Very Senior Member
You could backup the 3 hidden files located in /jffs/addons/YazDHCP.d (.staticlist,.hostnames and.optionslist) and create a dnsmasq.conf.add file in /jffs/configs that points to them.
Of course, going forward you would have to manage adds/changes/deletes.

IMHO, YazDHCP is pretty lightweight and enhances the standard DHCP static web ui (it's kind of behind the scenes).
I would add it after a fresh install.
 

pdc

Regular Contributor
I agree, I like YazDHCP since it adds the ability to save/restore the static mappings while still maintaining the usefulness of the WebUI configuration and icons. Otherwise there's no good way to save/restore the settings (it is technically possible with nvram parameters, but not straightforward at all).

Disclaimer: You can see from my signature I'm not the best person to ask for a simple setup :)
 

dave14305

Part of the Furniture
The other edge case is using a mask smaller than /24. That scenario could be ignored (255.255.254.0).
Given networkmap etc. assume a hardcoded /24 (unless that's changed) I have some wiggle room on ignoring that one
Time to wiggle! See this misplaced issue:
 

Jack Yaz

Part of the Furniture

Trigger911

New Around Here
Hello,

Really loving this addon. I just wanted to ask if there was a put a last seen counter on the export or if there was a way to query this.
 

Jack Yaz

Part of the Furniture
Also, in regards to the stripping, I suppose that could be addressed by doing real bit masking using the netmask, but that might overcomplicate things, especially for such a limited use case. That would dynamically adjust the max based on the netmask.

I did want to report it though and if it would be too restrictive for the general release, I totally understand. It wouldn't be the first time I've been told to "fork off" lol
sorry for the age its been to get to this. if you run
Code:
YazDHCP develop
i'd be happy if you can test if YazDHCP now behaves properly with a non /24 (it won't strip the first 3 octets)
 

John DeLuca

Regular Contributor
Hello it seems like i am having a minor issue, when i try to install it is not migrating my DHCP list to yaz, and when i try to add an address via the gui no mac addresses or devices show up on the drop-down menue. luckily everything was saved in nvram so i don't have to re-enter dhcp.
 

Jack Yaz

Part of the Furniture
Hello it seems like i am having a minor issue, when i try to install it is not migrating my DHCP list to yaz, and when i try to add an address via the gui no mac addresses or devices show up on the drop-down menue. luckily everything was saved in nvram so i don't have to re-enter dhcp.
router version, firmware version, any errors when you installed YazDHCP?
 

QuikSilver

Very Senior Member

John DeLuca

Regular Contributor
Yes I was but now that I think of it there may have been an error saying NVRAM was empty or something related. I have to reinstall and check when I get a minute
 

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