DHCP Logic

G I Jones

@dustinb3403 lol, trying to figure things out, man.

G I Jones

@dustinb3403 yea, that's exactly what I was saying, but I'm confused about what scott said. I don't get why he said that. Like no bearing on what?

DustinB3403

The critical thing to know here is "available for assignment".

Creating a reservation immediately makes that address "available for assignment" regardless of if its in the pool or not in any GUI you're looking at.

G I Jones

@dustinb3403 yea, I'm not confused about anything DHCP, just what scott said and what he meant.

G I Jones

@pete-s said in DHCP Logic:

It's another question but it's debatable if DHCP reservations is a good idea in the first place. In general I would say no.
Better to use static IPs, at least for anything that is important.

I disagree entirely. Here's why. You rely on a static IP for a printer right? Because you don't want them switching up all the time, but printers do go to standby mode, and then now you have a samsung phone (seems to always be the damn samsungs) that steals that IP and now the printer doesn't work. Happens all the time. I typically do both; I'll set a static IP for a printer, and then make the reservation on the DHCP server. This way nothing steals it. Additionally I'll do this same thing with anything of importance that has a static IP.

hobbit666

@g-i-jones For static IP's in a pool we will do an Exclude on that IP. That stops things from taking the IP as it removes it.,

DustinB3403

@g-i-jones said in DHCP Logic:

@pete-s said in DHCP Logic:

It's another question but it's debatable if DHCP reservations is a good idea in the first place. In general I would say no.
Better to use static IPs, at least for anything that is important.

I disagree entirely. Here's why. You rely on a static IP for a printer right? Because you don't want them switching up all the time, but printers do go to standby mode, and then now you have a samsung phone (seems to always be the damn samsungs) that steals that IP and now the printer doesn't work. Happens all the time. I typically do both; I'll set a static IP for a printer, and then make the reservation on the DHCP server. This way nothing steals it. Additionally I'll do this same thing with anything of importance that has a static IP.

But why not just statically assign an IP that isn't in the available pool? That IP would never be available to be handed out, and still statically assigned permanently.

G I Jones

@hobbit666 I see. Is there any benefits to doing exclude ip over just setting reservations in your opinion?

G I Jones

@dustinb3403 yea that would work too. the problem I seem to have about assigning ip that aren't in the available pool has always been how to see what ip's are being used. we have a big organization and some things I don't have my fingers in. I would hate to statically assign an IP to something that was already using it on accident.

DustinB3403

@g-i-jones that's true.

hobbit666

@g-i-jones No i prefer reservations but sometimes we have equipment that changes but want it on the same static IP

Obsolesce

I only exclude a small portion of an address pool within a scope for things like switches and such. This is usually the first 10 IPs, x.x.x.1 to x.x.x.10 for example. Everything else is available for DHCP lease, except obviously those IP addresses which are reserved. Those are restricted to specific MAC addresses.

DustinB3403

@obsolesce said in DHCP Logic:

Those are restricted to specific MAC addresses.

That's how reservations work

Obsolesce

@dustinb3403 said in DHCP Logic:

@obsolesce said in DHCP Logic:

Those are restricted to specific MAC addresses.

That's how reservations work

lies, all lies!

1337

@g-i-jones said in DHCP Logic:

I disagree entirely. Here's why. You rely on a static IP for a printer right? Because you don't want them switching up all the time, but printers do go to standby mode, and then now you have a samsung phone (seems to always be the damn samsungs) that steals that IP and now the printer doesn't work. Happens all the time. I typically do both; I'll set a static IP for a printer, and then make the reservation on the DHCP server. This way nothing steals it. Additionally I'll do this same thing with anything of importance that has a static IP.

Well, we use different ip ranges for static IPs and for dynamic IPs (reservations or not). That's why you can set the range in any dhcp server. And also in most cases we don't have any dhcp server on vlans for static IPs.

When the printer doesn't work IT support can just put a new one in it's place, go into the menu and change the static IP to what it should be and Bob's your uncle.

Same thing with IP cameras, switches and what have you.