printer installation with DHCP constant on

[BillyCarpenter]

Re: printer installation with DHCP constant on

That would only be the case when the the power is off long enough for temporary reservation created by the DHCP server expires. There is a problem with static addresses is that if the DHCP server does not know to reserve that address, it could easily assign that address to another device.

Most quality corporate IT personnel that I have worked with have had me set the machine up using DHCP. They would then set a permanent reservation. That avoided both potential problems though there would still be the problem of devices, often laptops, that connected with static addresses that the IT did not know about.

That's an interesting scenario, but why would a laptop user be connecting with a static IP address? Are we talking about wireless or a physical connection?

[slimslob]

Re: printer installation with DHCP constant on

DHCP is only useful when the IP is reserved by the customer. Using a DHCP obtained address is risky as a device that already has that address assigned statically could be switched off, then conflicts arise when it is switched on again. On any network install you want either a static IP address or a reserved DHCP.

DHCP can also cause problems with strangely behaving network hardware. I had a huge customer who had a rogue switch they were unable to track down that issued incorrect domain information on DHCP stopping the machines scanning to email. Setting the machine to a static IP and inputting the correct domain sorted this.

Some customers will not allow you to use a static IP but that's just a bridge you have to cross when you come to it I'm afraid.

I had a county water agency that switched from using the county's IT to using a local service, county often took 2 or 3 days to send someone out and the local took 1 or 2 hours. We put in a new Ricoh color MFP and the next day they couldn't print. When i got there I noticed an IP conflict message on the bottom of the screen. With a little network searching I discovered that somewhere in the building was a VPN that the county used to access water usage reports that was using the IP address I was initially given plus the next 2 for remote access.

[8T2]

Re: printer installation with DHCP constant on

That's an interesting scenario, but why would a laptop user be connecting with a static IP address? Are we talking about wireless or a physical connection?

I've ran into it where the wired and wireless DHCP addresses don't sync up properly and you end up with a duplicate IP even though both devices are on DHCP... arguing with IT over issues like that is the best when they refuse to admit the issue is on their side and expect you to prove it to them before they consider lifting a finger

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[slimslob]

Re: printer installation with DHCP constant on

That's an interesting scenario, but why would a laptop user be connecting with a static IP address? Are we talking about wireless or a physical connection?

More often than not it will be a hacker. They don't want their MAC showing up in the DHCP database.

[BillyCarpenter]

Re: printer installation with DHCP constant on

It's been interesting reading about the different ways to configure a copier to print.


-DHCP reservations

-Print to hostname

-Static IP address

I think all of those are pretty rock solid options but if you put a gun to my head and forced me to pick the most reliable? I'm going with static IP address.


Disclaimer: In slim's scenario where the customer kept changing ISP providers, that wouldn't be ideal.

[8T2]

Re: printer installation with DHCP constant on

It's been interesting reading about the different ways to configure a copier to print.


-DHCP reservations

-Print to hostname

-Static IP address

I think all of those are pretty rock solid options but if you put a gun to my head and forced me to pick the most reliable? I'm going with static IP address.


Disclaimer: In slim's scenario where the customer kept changing ISP providers, that wouldn't be ideal.

Direct static IP is the preferred way and the rest are just ways to get around IT's incompetence or etwor shortcomings.

I started messing around with DHCP on and Host name connections because of the scenario slimslob mentioned and because IPs were not reserved and constantly got called out because the devices went offline.

I had a few customers where I was fortunate enough to work with an IT guy as lazy as me that really wants to do the work once and sit back without issues going forward where I could implement all the methods in one.

They actually reserved the IP for the physical network point used for the device on the switch, I could leave DHCP on as a rollover failsafe, we agreed on host and print driver names that made sense to both of us and and it was done once and forgotten. I usually got together with them when taking over a opposition contract and implemented all the changes then with initial setup.

Combined with disabling WSD these were some of the tidyest installs around. No PC's with 20 different drivers installed of which 19 were obsolete old printers and something oddly satisfying about browsing a network and seeing the fleet of printers neatly grouped together.

I took it one step further and implemented a form of subliminal marketing if I had the chance to actually name the printers (our company name)Printer reception so users got bombarded with our name constantly when printing something or when they ask a colleague which printer to print to.

Horses for courses at the end of the day though

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[rthonpm]

Re: printer installation with DHCP constant on

The most important thing for any static IP addresses is to NOT have them in a range that DHCP assigns. DHCP doesn't have any means to recognise a static IP, only a reserved address. Using the example of a SOHO router: DHCP addresses are usually from x.x.x.100 to x.x.x.250 so your static IP's should be somewhere from .2 to .99. Some larger networks may have a larger subnet where the first segment is DHCP and the second is static so all of the static IP's for 10.0.20.0/23 would be 10.0.21.x and DHCP would be 10.0.20.x

DHCP reservations have become more and more common, especially with more segmented VLAN's so that all printers are in the same IP range: connect the printer to the right network and then just reserve the address for it on the DHCP server and done.

Any high availability device (printer, server, appliance, etc) should have either a static or reserved address. If you just rely on name resolution there's always a risk of DNS being out of date on the client machine and not being able to resolve a device if the IP has changed since the last DNS refresh of the device.

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[Mark Bbb]

Re: printer installation with DHCP constant on

The most important thing for any static IP addresses is to NOT have them in a range that DHCP assigns. DHCP doesn't have any means to recognise a static IP, only a reserved address. Using the example of a SOHO router: DHCP addresses are usually from x.x.x.100 to x.x.x.250 so your static IP's should be somewhere from .2 to .99. Some larger networks may have a larger subnet where the first segment is DHCP and the second is static so all of the static IP's for 10.0.20.0/23 would be 10.0.21.x and DHCP would be 10.0.20.x

DHCP reservations have become more and more common, especially with more segmented VLAN's so that all printers are in the same IP range: connect the printer to the right network and then just reserve the address for it on the DHCP server and done.

Any high availability device (printer, server, appliance, etc) should have either a static or reserved address. If you just rely on name resolution there's always a risk of DNS being out of date on the client machine and not being able to resolve a device if the IP has changed since the last DNS refresh of the device.

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Dear rthon, the imc series allow the dhcp to also fill in the DNS ip addresses automatically (as well as gateway).
So, no matter if the DNS, gateway or even the ip address changes in the network, our printer is still going to print.
I kind of like that...

[Mark Bbb]

Re: printer installation with DHCP constant on

Theoretically i like it, but how will it behave in real life?
And what about smb scanning?

[rthonpm]

Re: printer installation with DHCP constant on

Dear rthon, the imc series allow the dhcp to also fill in the DNS ip addresses automatically (as well as gateway).
So, no matter if the DNS, gateway or even the ip address changes in the network, our printer is still going to print.
I kind of like that...

DHCP assigns those by default, but keep in mind that DNS only refreshes on computers at regular intervals so if the address of the MFP changes before a client gets a DNS refresh they're not going to be able to print or scan. Even better: the refresh cycle happens per machine depending on the time they were powered on or brought out of sleep so in you could have half of an office able to print and the other half dead in the water. A printer is generally considered a high availability device so it should at minimum have a reserved address in DHCP.

[copier tech]

Re: printer installation with DHCP constant on

Dear 8T2, but still, how can customer enter the WIM, if ip address is changing without knowing it well?

I always turn on display IP address setting with SP5055 the IP address will be displayed at the top on the screen so the user can easily view it if asked.

[Mark Bbb]

Re: printer installation with DHCP constant on

DHCP assigns those by default, but keep in mind that DNS only refreshes on computers at regular intervals so if the address of the MFP changes before a client gets a DNS refresh they're not going to be able to print or scan. Even better: the refresh cycle happens per machine depending on the time they were powered on or brought out of sleep so in you could have half of an office able to print and the other half dead in the water. A printer is generally considered a high availability device so it should at minimum have a reserved address in DHCP.

Dear rthon, but at the other hand, DNS IP is not changing often, is it?
I do not see a benefit of changing DNS IP's often, or am i missing something?
When the printer would have a fixed DNS ip, and the DNS would change, then an intervention is needed, whereas with dhcp on, not, it will solve itself after some time...
No?

[Mark Bbb]

Re: printer installation with DHCP constant on

I was informed that printing or scanning over a vpn network would cause problems with dhcp constant on.
So, fixed ip is (meanwhile) still the best.

[rthonpm]

Re: printer installation with DHCP constant on

Dear rthon, but at the other hand, DNS IP is not changing often, is it?
I do not see a benefit of changing DNS IP's often, or am i missing something?
When the printer would have a fixed DNS ip, and the DNS would change, then an intervention is needed, whereas with dhcp on, not, it will solve itself after some time...
No?

The issue isn't with the IP of the DNS server changing, but rather with the clients that report back to the server changing their IP's.

Put simply: when your computer gets an IP from DHCP, it also reports to the internal DNS servers to say that hostname X now has IP address Y.
Your local machine also caches some DNS records for easy recall, and then checks back to the DNS server at a regular interval (usually around 90 minutes) for any changes to that cached copy.

Let's say that a number of devices go offline that are purely DHCP. When they come back up, they may not pull the same address. Your computer stayed up the whole time and still knows just the old IP addresses since it isn't time for a new cache check. In and instance like this, you either need to manually flush the DNS cache on the local computer to pull a new copy with the updated addresses (which requires admin rights), or you need to wait until the next DNS refresh. In a sufficiently large environment, neither of these options is really that good of a choice. This is why things like DHCP reservations exist, to allow devices to always pull the same address with no need to manually configure the device. For things like a workstation that are more or less a client system (i.e. it accesses other resources) straight DHCP is fine. For any resource that other access (i.e. it's serving something), you want to ensure that it's readily and predicatively available so you want it to have some kind of well known address.

If you're going to use DHCP for setting up devices: get a reservation for the IP. If you're going to use a static IP, don't use one in the range of addresses that DHCP doles out. The difference between the two generally comes down to how long it will stay around: printers get replaced much more frequently than servers so a DHCP reservation makes sense since it's plug it in, let it get an address, then lock it down as a reservation in the DHCP console of choice.

[Mark Bbb]

Re: printer installation with DHCP constant on

The issue isn't with the IP of the DNS server changing, but rather with the clients that report back to the server changing their IP's.

Put simply: when your computer gets an IP from DHCP, it also reports to the internal DNS servers to say that hostname X now has IP address Y.
Your local machine also caches some DNS records for easy recall, and then checks back to the DNS server at a regular interval (usually around 90 minutes) for any changes to that cached copy.

Let's say that a number of devices go offline that are purely DHCP. When they come back up, they may not pull the same address. Your computer stayed up the whole time and still knows just the old IP addresses since it isn't time for a new cache check. In and instance like this, you either need to manually flush the DNS cache on the local computer to pull a new copy with the updated addresses (which requires admin rights), or you need to wait until the next DNS refresh. In a sufficiently large environment, neither of these options is really that good of a choice. This is why things like DHCP reservations exist, to allow devices to always pull the same address with no need to manually configure the device. For things like a workstation that are more or less a client system (i.e. it accesses other resources) straight DHCP is fine. For any resource that other access (i.e. it's serving something), you want to ensure that it's readily and predicatively available so you want it to have some kind of well known address.

If you're going to use DHCP for setting up devices: get a reservation for the IP. If you're going to use a static IP, don't use one in the range of addresses that DHCP doles out. The difference between the two generally comes down to how long it will stay around: printers get replaced much more frequently than servers so a DHCP reservation makes sense since it's plug it in, let it get an address, then lock it down as a reservation in the DHCP console of choice.

Rhon, in fact you describe the printer the same way as you describe a host or pc in that network, with a hostname (and "floating" ip address)
So, the thing is to just make a fixed ip not in the printer, but in the dhcp server itself, ok.
But will this setup allow vpn printer requests (f.i. printing from home)? And scanning, you didn't mention that part either ...