Smoothwall - Bumping a device off DHCP?

[kcalderw]

I have a printer that is statically assigned in DHCP. The printer was offline for the summer and it seems another device that is set to auto grabbed the printers address. I'm trying to boot off this other device if I can but I do not recognize the name to easily unplug it. Is there a way in Smoothwall to boot it off DHCP?

[Davit2005]

I have a printer that is statically assigned in DHCP. The printer was offline for the summer and it seems another device that is set to auto grabbed the printers address. I'm trying to boot off this other device if I can but I do not recognize the name to easily unplug it. Is there a way in Smoothwall to boot it off DHCP?

 

Have you got another DHCP server giving out addresses in the same scope/subnet? and you have overlapped IP addresses?

 

Can you search by MAC address for the IP on the smoothwall? And then I suggest if you are overlapping you need to sort that out :-)

[kcalderw]

No, no other DHCP servers. The static assignment was for a printer that was offline for a long time over the summer. Someone plugged in a laptop to a data port on a VOIP and somehow that device grabbed the static IP of the printer. I traced everything back manually today and finally found the device. I have it all sorted now, I just couldn't find a way to disassociate the device in the Smoothwall to bump it off so it would reacquire a new IP.

[Davit2005]

No, no other DHCP servers. The static assignment was for a printer that was offline for a long time over the summer. Someone plugged in a laptop to a data port on a VOIP and somehow that device grabbed the static IP of the printer. I traced everything back manually today and finally found the device. I have it all sorted now, I just couldn't find a way to disassociate the device in the Smoothwall to bump it off so it would reacquire a new IP.

 

OK, maybe wrongly I assumed by static DHCP you used a DHCP reservation and could not understand why this was then used any any other device, lol.

Edited September 21, 2020 by Davit2005

[ITGURU]

I don't understand why people 'static' ips using DHCP reservations! If it's a core network item, give it a static IP properly!

[DrBeaker]

I don't understand why people 'static' ips using DHCP reservations! If it's a core network item, give it a static IP properly!

I think the advice has changed multiple times over the years.

 

Statics are OK until you've got a fleet of devices e.g. printers and have to manually update them, enter the info etc.

 

Best advice I read was to put statics on things like switches etc and in the event of DHCP issues you know you can still get to them. Whereas with a printer it wouldn't matter so much.

[ITGURU]

What if you have 2 dhcp servers for redundancy, you have to add the details to the other server because if you reserve on one dhcp server and the printer devices to get a request from the other server , it'll end up with a different IP?

I static everything that will be static on the network, switches, cctc, printers, access control, APs, etc. DHCP is just used for clients.

[Davit2005]

What if you have 2 dhcp servers for redundancy, you have to add the details to the other server because if you reserve on one dhcp server and the printer devices to get a request from the other server , it'll end up with a different IP?

I static everything that will be static on the network, switches, cctc, printers, access control, APs, etc. DHCP is just used for clients.

 

We use InfoBlox for DHCP here so it is a bit easier. InfoBlox was way ahead of Windows for DHCP redundancy and it probably still is. We also have about a thousand subnets so an IPAM solution makes it a hell of a lot easier.

 

Personally I still prefer to add reservations for Printers, this is because I have seen many times before Printers lose their static settings. Having registrations is also a good record of what IP addresses have been used and stop the DHCP server giving these addresses to other clients, also gives you the flexibility that you only need change the reservation to change the IP address. My first job looking after a network there were static IP addresses everywhere and whilst this is OK there needs to be a method of knowing what is used etc. or documentation

 

INMO Servers, Switches should defo be static but as I say it depends on the needs, everyone sees a different need, some system may work for one org but not necessarily for another.

Edited September 22, 2020 by Davit2005

[Primus]

What if you have 2 dhcp servers for redundancy, you have to add the details to the other server because if you reserve on one dhcp server and the printer devices to get a request from the other server , it'll end up with a different IP?

I static everything that will be static on the network, switches, cctc, printers, access control, APs, etc. DHCP is just used for clients.

 

If you're using multiple DHCP servers for redundancy then make use of a properly redundant DHCP system where they exchange records constantly so you only need to maintain the records in one place.

 

Best practice definitely has to be hard set statics on key infrastructure like switches and DHCP reserved addresses for devices such as printers. If for any reason you ever need to change scopes or re-IP your entire network then you've got a major job on with all those hard set IPs.

[Zammo]

I don't understand why people 'static' ips using DHCP reservations! If it's a core network item, give it a static IP properly!

 

Do both is my usual suggestion. Pros and Cons to each approach

 

One thing that has always annoyed me about Windows DHCP is you cant put a comment against a reservation

[FN-GM]

I don't understand why people 'static' ips using DHCP reservations! If it's a core network item, give it a static IP properly!

 

We have a network that consists of 20 sites. Some of them are a plane journey away. If we use DHCP with reservations we can make a change centrally instead of visiting the device.

[Davit2005]

On the note of documentation, there is a free version of InfoBlox which can keep track of IP addresses used but I have setup PHPiPAM at home which offers scheduled scans, multiple IPv4/IPv6 Subnets and can get DNS names direct from DNS servers.