Need a router i can set to have a 5 minute DHCP lease time,

[bradness]

Hi All,

 

Anyone know any makes of router i can set with a 3/4 or 5 minute DHCP lease time? 

 

Most makes i have tried have set time starting at 1 hour minimum.

 

I have searched all over the internet and only comments that seem to be floating about are the "why bother" and "you would never need one"

 

but this is exactly what i need, If anyone knows of one then any info would be great.

 

Thanks

[Circaflex]

I dont know of a router off the top of my head, but I do know DDWRT allows you to do this. You might be able to run ddwrt on your current router.

[oldtimefighter]

Why do you need this?

[+BudMan MVC]

You do understand you don't have to run dhcp on your router, you can run dhcp on any linux box or windows server comes with it or you could run

 

http://tftpd32.jounin.net/

 

has dhcp server.. Lots of different ways to skin this cat.. Pretty sure 3rd party firmware for soho routers like dd-wrt have more options for dhcp server as well.

 

But I have to ask why do you want/need such a short lease time?

[bradness]

i work with multiple devices per day all set to Auto Ip from the start, rather then issuing each one with a set IP address i need a low DHCP time so i can plug a lead in, have it issue my device with the same IP each time, do a 5 minute set up and then clear the address ready for the next device. 

 

 

[+BudMan MVC]

huh??

 

So you have device1 and you want to get IP address 192.168.1.100, then you want to plug in device2 and get same 192.168.1.100 address?

 

What is the use case, what does is matter if device2 gets .101, device3 gets .103 etc..

[bradness]

thanks for the info regarding dd-wrt, will give this a try, i am using a computer that has many restrictions so 3rd party software is a no go, hence looking down this route.

 

many thanks for your replies.

[bradness]

that is correct, many devices all needing the same ip one at a time, i have a program i made using autohotkey that automates a set up for each so rather then changing the Ip to match each box, i can run the program on repeat without having to touch it. 

[+BudMan MVC]

yeah so dd-wrt sure looks like you could set lease time to 1 minute

 

Just grabbed that from an emulator site, I don't currently have it running I use pfsense for my router.  And that allows full control over dhcp options so you could set your 1 minute lease time if you wanted.

 

[bradness]

that sounds perfect for i want, i have an old netgear router i can give it a go on, Default firmware currently allows minimum time of something like 30 mins, 

 

Thank you all for your replies, Much appreciated. 

[+BudMan MVC]

why don't you just have your script pull the IP of the machine??

[sc302 Veteran]

Or just run a script that inserts the ip when you need it.  over thinking things a bit much....

[+BudMan MVC]

^ yeah I am not really understanding the use case here.. Either have your script get the ip, or just have it set the IP of the machine and don't use dhcp, etc..  Confused and curious

[bradness]

not that good with scripts to be honest, this seemed like a much easier option as i was already using a router for wireless connection to the Device. 

 

Surely plugging my Ethernet lead in and automatically getting the desired Ip for the duration i need it is better then Writing/testing code?

[+BudMan MVC]

Here is the thing.. Even if your lease time is only 1 minute.. Depending on the way the dhcp server works you might not get first IP in pool or last IP, etc.. it might walk down the pool because its a new mac and might not reassign the same IP from the pool even if the previous lease expired, etc.

 

It could keep the expired lease there until its pool has been exhausted before it starts using up expired leases.  So device1 might get 192.168.1.100, with 1 minute lease.  Then you turn off that machine sure the lease expires.  But then comes along device2 with different mac and the dhcp server could give it 192.168.1.101 since it had not been assigned yet, etc.  And 100 has a previous lease tied to a different mac, even though it is expired there are plenty of IPs left in the pool.

 

Guess you could make it pool of 1 IP

[bradness]

ok, you have me curious now, how would i go about "inserting" or "setting" the desired ip using code?

 

not asking for you to write me code, just a general helpful tip. 

 

I cant use installable programs, im only just getting away with running scripts.

[sc302 Veteran]

if a windows computer

 

 

 

netsh interface ip set address "Local Area Connection" static 192.168.1.100 255.255.255.0 192.168.1.1

netsh interface ip add dns "Local Area Connection" 8.8.8.8

netsh interface ip add dns "Local Area Connection" 208.67.220.220 index=2

 

 

 

put that into a networkip.bat file and run as administrator.

[bradness]

i thought about this kind of thing but these devices need finish on Autoip, i was looking at ways of keeping the settings to a minimum plus they reset once a static address has been allocated and also again once dynamic has been reselected adding more time to the set up process,

 

really appreciate your ideas, its all stuff i will be trying. 

 

 

[+BudMan MVC]

well just set back to dhcp via netsh then when your done with whatever else your doing..

 

netsh interface ip set address "Local Area Connection" dhcp

netsh interface ip set dns "Local Area Connection" dhcp

 

What do you mean they reset??

[sc302 Veteran]

or just make a configuration and image it so that it retains your configuration....no need to reset whatever service back up. 

[bradness]

thanks for the advice, few issues i have come up against while using these ideas. 1, this will add two reboots to the set up of my devices, they reboot every time a network change has been issued, part of my setup involves turning IPV6 off and i do this last just so the reboot signifies the end of the set up. Also i have tried before to use images and scripts to make changes and been hit with problems due to the device needing username and password before changes can be made. 

 

The devices in question are Printers or MFD's, they have mini internal print servers as well as a ever increasingly complicated operating system. 

 

 

 

[+John Teacake MVC]

I really dont get this thread, Why use a DHCP server at all. Just assign Statically, Whatever kind of device it is. Then document it in some shape or form?

[bradness]

ok lets assess the situation, i have multiple devices all needing the same set up which i can do through scripts that take less then 5 mins,

 

The Devices come in with DHCP set on and if the Device is turned on will obtain an ip the router has given it, every device will get a different ip within the hour as the DCHP lease time of the router is 1 hour minimum. 

 

currently i am manually assigning the same ip to each one by physically using the touch screen on the device to go into admin and setting a static ip, This then requires a restart of the machine, then running the set up then again logging into the admin mode to reset turn back on the autoip configuration ready for shipment. 

 

What i would like is a way so when i turn the Device on, the router gives it a set Ip address (the first one in the DHCP table), run the set up then when finished unplug it, the router then reaches its DHCP lease time, deletes the device from its table and the same ip address is then ready for the next device when i am ready.

 

Im trying to find ways of not setting the machine to static then back to auto, the router does all this for me. i just need the lease time to be shortened. 

 

not understanding why everyone needs to know why i need it it, look at the post, its nothing to do with my original question, believe me, it works this way, i have tested it many times bu turning the router off and leaving it off till it resets. And apparently I'm the one overthinking things. I have my answer so thank you very much. 

[+Warwagon MVC]

Are these desktop systems? Maybe you could use a USB ethernet adapter and set to a static IP. That way everytime you need to hook it to the network you hook it through that. Not sure if you can set it as static and still unplug and plug it back in.

[bradness]

good idea warwagon, unfortunately the devices are stand alone printers and multi functional devices (Copy/Fax/Scan/Print) etc. they have limited connectivity before their set up. Im pretty sure external network cards would require drivers and internal set up. 

 

thanks though.