[Frakko]

Netgear R7800 - Firmware: DD-WRT v3.0-r59661 std (02/14/25)
Hello, I created two VLans with address 10.10.10.1/29 10.10.11.1/29. I assign DHCP to clients. The problem is that the first client that connects to the router gets address 10.10.1x.7! In practice, the broadcast and the client is, of course, not able to navigate and communicate.
Is it a bug

[lexridge]

Since your start address is 2, I believe your Max should be set to 5, not 6.

Also, the first one in the dhcp server list has a subnet mask of 28 (not 29 as mentioned in your post), so it's max could be as high as 13, again since you are starting with 2.

[kernel-panic69]

The 10.10.20.1 subnet in the screenshot is 29, which shouldn't get a .7 DHCP assignment. Max usable hosts, including dhcp server is 6. I'm hesitant to say that this is a bug yet.

[lexridge]

@kp69 You said it better than I did. Given that his start address is .2 with a max of 6 addresses, that would make the last address 10.10.20.7 which of course is NOT usable as it's the broadcast address. So there may be a bug in that the dhcp server should not assign anything above 10.10.20.6 with a subnet of /29 and a network address of 10.10.20.0, regardless of the Max setting.

I may test this later, time permitting.

[ho1Aetoo]

The DHCP server does not know any subnets, it does what you configure.
And if you configure nonsense then you will also get nonsense.

We're already used to that from the OP

[lexridge]

Ah, I was unaware the dhcp server is ignorant to the subnet. So it's definitely not a bug, just a bad configuration. No need to bother testing now that I know this. lol

[kernel-panic69]

Deja Vu (read both pages of thread). No matter how many times you tell someone something, it doesn't register.

[Frakko]

The mistake arises from the fact that "MAX" is ambiguous. It is not clear whether the maximum refers to the number of configurable hosts or to the last IP. You have to put MAX (HOSTS) or an explanatory wording on the right, it would be advisable. On the /28 I typed wrong and it must have been /29 too. I hadn't noticed. I also tried starting from 1 to 6 but it doesn't seem to work correctly, (IP 1 is not addressed correctly, 10.10.10.0/29) I don't waste any more time in case you do the tests. Greetings.

[Alozaros]

https://www.youtube.com/watch?v=OqsXzkXfwRw

https://www.freecodecamp.org/news/subnet-cheat-sheet-24-subnet-mask-30-26-27-29-and-other-ip-address-cidr-network-references/

https://www.calculator.net/ip-subnet-calculator.html

DDWRT/DNSmasq DHCP is not that different...you can even start either from .64 or .100
you can use dhcp-sequential-ip to get the next available IP but, sadly it doesn't work like this always..

my personal experience...you have to be careful and know what you are doing...the use of /24
is the best...that...you can limit the IP range with DNSmasq and choose where to start..
so if you set limit at DHCP given IP to 8 and start from .100.....that would mean .100-.107 included..
as simple as that..

but as

[kernel-panic69]

We're not here to fix your continued misunderstanding of basic IP subnet concepts. If I am not mistaken, this is the same "wording" regardless of what firmware is being used. This is a gross misconfiguration on your part, as already pointed out. Bye!

[Frakko]

[ho1Aetoo]

There's nothing to test and you're annoying us with your nonsense.

When you create a new DHCP server the settings are start=100 and max=50
So question answered??

The last IP address is 149 and cannot be 50 because it only starts at 100.

Always the same stupid questions from you... if this is too difficult for you then don't play around with it and use full /24 subnets like any normal person.

Topic closed

[kernel-panic69]

I concur on topic closed. You were given the same answer over 8 - almost 9 years ago on how to fix this. There is nothing to fix except entering the correct value.

EDIT/UPDATE: Here's your "verification test":