Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


82 posts

Master Geek

Trusted

Topic # 151770 4-Sep-2014 15:16
Send private message

Hello, if I have a bunch of printers with static IP addresses, and I establish a new DHCP server, how does the DHCP server realise that those static IP's are already in use ?
Does the DHCP server send out a query on the network before it allocates addresses ?

Thanks for any info.

Create new topic
142 posts

Master Geek
+1 received by user: 8


  Reply # 1121904 4-Sep-2014 15:19
One person supports this post
Send private message

Hi,

Nope, the DHCP server will not take any notice - you will need to reserve those addresses from the new DHCP scope otherwise you'll get dupe IP issues.

Cheers

2382 posts

Uber Geek
+1 received by user: 694

Trusted
Lifetime subscriber

  Reply # 1121907 4-Sep-2014 15:20
Send private message

If you are using the same operating system and DHCP software, you should be able to export and import the settings.

Some DHCP Servers can be configured to test (ping) an IP address before handing it out.

Otherwise, just enter these static IP addresses as a Reservation or an Exclusion manually into your DHCP software.




"4 wheels move the body.  2 wheels move the soul."

“Don't believe anything you read on the net. Except this. Well, including this, I suppose.” Douglas Adams

Doesn't know what he doin
2879 posts

Uber Geek
+1 received by user: 369

Subscriber

  Reply # 1121908 4-Sep-2014 15:21
One person supports this post
Send private message

We've just covered DHCP servers in one of my lectures this week actually :D

You'd simply add the range of static IPs currently issued, into an Exclusion on the DHCP server. That way it won't issue those IPs to anything. You do the same thing to ensure servers and the like have a static IP.




Bachelor of Computing Systems (2015)

 

--

 

Late 2013 MacBook Pro with Retina Display (4GB/2.4GHz i5/128GB SSD) - HP DV6 (8GB/2.8GHz i7/120GB SSD + 750GB HDD)
iPhone 6S + (64GB/Gold/Vodafone NZ) - Xperia Z C6603 (16GB/White/Spark NZ)

Sam, Auckland 


18 posts

Geek
+1 received by user: 2


  Reply # 1121946 4-Sep-2014 15:48
One person supports this post
Send private message

initially the dhcp server wont know that the ip addresses have been assigned statically to a device. it will offer the address to the client that that is requesting an address. the client should then test this address and if it finds it is in use it will send a DHCPDECLINE message back to the dhcp server. the client will then start the request for an ip address again. the dhcp server should then mark the declined ip address as a bad address and not try and give it out anymore

this is how it should work in theory.

you could make life simpler by setting the start of range of the addresses being handed out above the ip addresses of the printers. this will also allow you to manually assign other ip addresses in the low range you know is always available

4025 posts

Uber Geek
+1 received by user: 1076

Trusted

  Reply # 1122051 4-Sep-2014 18:20
Send private message

Either put your static devices outside of the DHCP scope (but still within the subnet), or create reservations. Nice thing about reservations is that if you reset the configuration on those printers, itll just jump straight back on the right IP.

658 posts

Ultimate Geek
+1 received by user: 28


  Reply # 1122063 4-Sep-2014 18:42
Send private message

If you have to use static IP's for your printers it's probably better that you set them up in your DHCP server (mapping via mac address) instead of hard-coding on each individual printer.
Otherwise, would be a wee bit of an administrative nightmare I would've thought.

4955 posts

Uber Geek
+1 received by user: 1318

Trusted
Microsoft

  Reply # 1122112 4-Sep-2014 19:53
Send private message

some DHCP servers have the option to test if an address is already in use before it hands out an address that would conflict.  Windows Server DHCP comes to mind.

833 posts

Ultimate Geek
+1 received by user: 260

Trusted

  Reply # 1122130 4-Sep-2014 20:36
Send private message

nathan: some DHCP servers have the option to test if an address is already in use before it hands out an address that would conflict.  Windows Server DHCP comes to mind.


Circa Windows Server 2008 yes :-)

Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

N4L helping TAKA Trust bridge the digital divide for Lower Hutt students
Posted 18-Jun-2018 13:08


Winners Announced for 2018 CIO Awards
Posted 18-Jun-2018 13:03


Logitech Rally sets new standard for USB-connected video conference cameras
Posted 18-Jun-2018 09:27


Russell Stanners steps down as Vodafone NZ CEO
Posted 12-Jun-2018 09:13


Intergen recognised as 2018 Microsoft Country Partner of the Year for New Zealand
Posted 12-Jun-2018 08:00


Finalists Announced For Microsoft NZ Partner Awards
Posted 6-Jun-2018 15:12


Vocus Group and Vodafone announce joint venture to accelerate fibre innovation
Posted 5-Jun-2018 10:52


Kogan.com to launch Kogan Mobile in New Zealand
Posted 4-Jun-2018 14:34


Enable doubles fibre broadband speeds for its most popular wholesale service in Christchurch
Posted 2-Jun-2018 20:07


All or Nothing: New Zealand All Blacks arrives on Amazon Prime Video
Posted 2-Jun-2018 16:21


Innovation Grant, High Tech Awards and new USA office for Kiwi tech company SwipedOn
Posted 1-Jun-2018 20:54


Commerce Commission warns Apple for misleading consumers about their rights
Posted 30-May-2018 13:15


IBM leads Call for Code to use cloud, data, AI, blockchain for natural disaster relief
Posted 25-May-2018 14:12


New FUJIFILM X-T100 aims to do better job than smartphones
Posted 24-May-2018 20:17


Stuff takes 100% ownership of Stuff Fibre
Posted 24-May-2018 19:41



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.