[SOLVED] Static and Reserved IP priority?

[CM-14]

I am working with network printers in my office and would like to know if a device can get a statically requested IP if there is a reservation on that IP by another device, and that device is offline? IE: do static requests ignore reservations if the IP is available? Thanks!

 

[kanewolf]

I am working with network printers in my office and would like to know if a device can get a statically requested IP if there is a reservation on that IP by another device, and that device is offline? IE: do static requests ignore reservations if the IP is available? Thanks!

A static IP address is done on the device and it does not know about or care about a DHCP reservation. Since a static address is a manual step, there is no "available IPs". You are setting up for duplicate address problems.

 

[bill001g]

Not sure what you are asking. There really no standard method of making a IP addresses redundant between devices.

So the way IP addresses reservations work by default is if actually statically set the IP the end device it will always use that IP even if another device is using the same IP. You might get a message about duplicates but it will continue to try to use it. This is always the risk you take with static IP.
The next relates to how the DHCP server works. A good dhcp server will try to ping a IP before it gives out a IP just in case there is a static IP or maybe the DHCP server rebooted and no longer has a record but there are end device still using IP they received previously via DHCP. This mostly will prevent duplicates.
The other standard method is using what is called a static DHCP reservation. This is similar to a static IP set in the end device but you set the DHCP server to always give the end device ie mac address, the same IP.

If you want a multiple devices to share a IP address say as a backup, lets say it is not possible for a home user. They way this is commonly done is with a DNS server so that the same name can be tied to multiple IP addresses. This can be done for both load balancing and backup. The end devices actually have different IP addresses
but they share the same name. Now there are special cases like google dns ...ie 8.8.8.8. This is actually a duplicate address but it is not on a lan. They are doing this trick using a router and routing protocols.

 

[Ralston18]

So if two devices are assigned the same static IP and both are online then there will be an IP address conflict.

And do not forget MAC's. MACs identify a unique device. A static IP being reserved for particular MAC.

Hopefully the router would prohibit such configurations and/or conflicts.

Details vary with the router.

https://www.online-tech-tips.com/co...p-address-to-a-printer-or-any-network-device/

So my answer is no.

 

[falcon291]

I am working with network printers in my office and would like to know if a device can get a statically requested IP if there is a reservation on that IP by another device, and that device is offline? IE: do static requests ignore reservations if the IP is available? Thanks!

You must assign those printers with their MAC ID in your DHCP server to different IP addresses.

 

[CM-14]

Thanks for the responses. Just to explain my situation. I work site support for a large company and do not have access to the DHCP server is create reservations. It easiest for me to use static IPs and I do not want DHCP to hand those address out when the static devices are offline. I was denied when I requested to set aside a scope that DHCP would not hand out. My solution is to request that "phony" reservations be created for the IPs that I want to use statically, thus preventing them from being handed out.

 

[falcon291]

Thanks for the responses. Just to explain my situation. I work site support for a large company and do not have access to the DHCP server is create reservations. It easiest for me to use static IPs and I do not want DHCP to hand those address out when the static devices are offline. I was denied when I requested to set aside a scope that DHCP would not hand out. My solution is to request that "phony" reservations be created for the IPs that I want to use statically, thus preventing them from being handed out.

The company I am working reserved a whole block for printers. So they have different IPs than servers and user computers. All are in different blocks. It is the best practice.

If you are not allowed to have IPs for your printers, then if somehow one of your printers becomes offline, there is no guarantee that it can get the same IP. Your requests are legit, but I cannot say the same for their replies.

 

[kanewolf]

Thanks for the responses. Just to explain my situation. I work site support for a large company and do not have access to the DHCP server is create reservations. It easiest for me to use static IPs and I do not want DHCP to hand those address out when the static devices are offline. I was denied when I requested to set aside a scope that DHCP would not hand out. My solution is to request that "phony" reservations be created for the IPs that I want to use statically, thus preventing them from being handed out.

Your network admins are clueless. There should be a range, that is not part of the DHCP scope. But they want the power, so they say "no", and it justifies their job. That is a political battle that needs to go to your manager and to the common manager between client support and networks.

 

[hang-the-9]

Thanks for the responses. Just to explain my situation. I work site support for a large company and do not have access to the DHCP server is create reservations. It easiest for me to use static IPs and I do not want DHCP to hand those address out when the static devices are offline. I was denied when I requested to set aside a scope that DHCP would not hand out. My solution is to request that "phony" reservations be created for the IPs that I want to use statically, thus preventing them from being handed out.

If you set something up as a static IP that is not removed from the range of the DHCP server, you are likely to get IP conflicts since the DHCP server has no idea about what IP is setup as static on what device. Talk to your manager and have them escalate this. It makes 0 sense not to provide you with static IPs if needed. If whatever you are doing needs to have a static IP that is a business requirement that network/server group has to deal with, it's a perfectly normal thing to have static IPs and I have never in 30 years of IT work have heard of someone being denied use of them. The business drives the IT not the other way around.

 

[faalin]

If the printer absolutely can not run on DHCP and has to be statically assigned then ask the IT department what IP address to use or if there is a block set aside for printers. If they dont give you one or wont then assign it the same IP address as a network switch.


When it starts causing issues just tell them you didnt give me a IP address to use, or a set block to put it in so i just picked one.

 

[Ralston18]

This:

"If they dont give you one or wont then assign it the same IP address as a network switch. When it starts causing issues just tell them you didnt give me a IP address to use, or a set block to put it in so i just picked one. "

No. Do not do that.

Such things can easily backfire. AKA the Law of Unintended Consequences....

You may end up in trouble.

Escalate to your manager per @kanewolf in Post #8.

Not sure why you are the one working with the network printers in your office to begin with? Especially with respect to network connectivity.

That should be the purview of the network admins and within their responsibilities.

Again, do not mess with the printers and let management sort it all out.

Just my thoughts on the matter.

 

[kanewolf]

This:

"If they dont give you one or wont then assign it the same IP address as a network switch. When it starts causing issues just tell them you didnt give me a IP address to use, or a set block to put it in so i just picked one. "

No. Do not do that.

Such things can easily backfire. AKA the Law of Unintended Consequences....

You may end up in trouble.

Escalate to your manager per @kanewolf in Post #8.

Not sure why you are the one working with the network printers in your office to begin with? Especially with respect to network connectivity.

That should be the purview of the network admins and within their responsibilities.

Again, do not mess with the printers and let management sort it all out.

Just my thoughts on the matter.

VERY MUCH AGREE. Doing things which you KNOW are reckless will get you disciplined or terminated.