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Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
654     0

How do I add a single reserved ip without having Infoblox setting it as DHCP and push out an useless conf on the servers? 

 

So far only seen I can do this when adding a range, where there's an option to disable from DHCP 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
654     0

Anyone who can help me with this, can you reserve a single ip adress in Infoblox IPAM without it being treated as a fixed DHCP writing 7 rows of config in dhcpd.conf? 

 

 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Expert
Posts: 277
654     0

Sounds like you are trying to add fixed address, when really you need "IPV4 Reservation". Navigate to a VLAN in IPAM and it's on the toolbar on the right, just click "Add" and you'll see it in the drop-down menu.

Paul Roberts
PCN (UK) Ltd

All opinions expressed are my own and not representative of PCN Inc./PCN (UK) Ltd. E&OE
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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
655     0

Thanks Paul,

If I go to a subnet in the IPAM, Add - IP4 reservation the reserved ip shows up with Type Reservation and Usage DHCP, and a Fixed IP conf with  MAC 00:00:00:00:00:00 gets pushed to server. This is the same if I do so within or outside of the regular DHCP scope.  

 

If I instead go Add - Range - IPv4 there is an option to tick box "Disable for DHCP" resulting in Type IPv4 Reserved Range without DHCP and no DHCP conf pushed to server. 

I noticed just now I can choose a range of a single ip address which is great and could be doable workaround, but strangely enough that non-dhcp range isn't possible to remove in IPAM view but only in DHCP view. 

 

I could possible get the local support team start using Range instead of Reservation (can I block Reservation in the permissions for them? ) , but adding to that they'd have to go to DHCP view to remove it just seems out of place.

 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Expert
Posts: 277
655     0

I think you're doing something wrong, you don't need to go into the DHCP view, nor do you need to define a range. Stay in the IPAM view, just add a Reservation not a Fixed Address. The system does not prompt me for a MAC address, see screenshots:

 

ib reserve 1.jpgib reserve 2.jpg

 

 

Paul Roberts
PCN (UK) Ltd

All opinions expressed are my own and not representative of PCN Inc./PCN (UK) Ltd. E&OE
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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
655     0

Hi Paul,

It looks like we have a bit of a misunderstanding here, or perhaps different Infoblox versions handled this differently. 

My pre-conditions is a subnet with a member assigned, there's a DHCP range and static ip's.

 

If I add a single Reserved ip address I go into the same 5 step Wizard where step 3 is DHCP options and outcome is a DHCP reservation, Infoblox at this point also gives a notification DHCP services on the member needs to be restarted.

-You are right theres' no prompt for MAC but nonetheless Infoblox treats the Reserved ip as it's a DHCP entry 

 

Choosing to add a Range there's in the second step of the Wizard an option to tick "Disable for DHCP", resulting in a IPV4 Reservered Range without DHCP. Choosing those IP's (All or single doesn't matter) the Reclaim button is greyed out and it's first in the DHCP view it's possible choosing the Reserved Range and remove

 

 

Side note: What's the requirements for adding photos? Tried with both .png and .jpg but none seemed to work

 

 

 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Expert
Posts: 277
655     0

What version are you using? I'm on 8.5.1 here. The behaviour you describe might how an earlier version behaves, but to be honest I have been through so many versions now (I started on 3.x) that I can't remember how they all behave, even 8.4 has been popped off the stack already. :-)

Paul Roberts
PCN (UK) Ltd

All opinions expressed are my own and not representative of PCN Inc./PCN (UK) Ltd. E&OE
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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
655     0

Yeah could be a version thing, I'm on 8.3.8 but we'll upgrade shortly 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Authority
Posts: 16
655     0

It sonuds like what you are trying to achieve is: add a reservation (fixed address with all 0's for MAC), but does not need to restart the DHCP service.

 

There is a setting in the Grid DHCP Properties that will let you accomplish this:

 

Data Management --> DHCP, Toolbar --> Grid DHCP Properties, toggle Advanced.

 

Select General --> Advanced (horizontal tab),  there should be a checkbox that reads: Immediate FA Configuration: Enable immediate fixed address configuration changes. 

 

By checking this checkbox, you should be able to add both reservation and fixed addresses in the future, without restarting DHCP services.

 

 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
655     0

Hi,

Not really, what expected out of this was an option for adding reserved ip addresses without it writing 7 rows in the config of DHCP server. 7 rows may not sound like much but it adds up, on the first server I looked there's not only

59 000+ rows of those fixed IP's with only 0's in the MAC but they even take up 55% of the dhcpd.conf file. 

 

I stopped checking after one single server, just may do a global count soon. 

 

Not all are reserved as some are hosts with DHCP box ticked but at least for those I can fix it with a script, the reserved as it seems not. 

 

Not bothered about the restart of DHCP services, it's me and a few others who has this access globally and the rest can do it within their own country. 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Expert
Posts: 277
655     0

I had a quick play, I think I understand what you're saying now, I also see a fixed address get written out to the conf file, the reason I didn't see this before was because my subnet didn't have any members assigned, but now I have assigned one I see this in the config file:

 

subnet 10.251.5.0 netmask 255.255.255.0 {
	ddns-domainname = config-option domain-name;
	ddns-hostname = pick ( option fqdn.hostname, option host-name );
	option host-name = config-option server.ddns-hostname;
	host 10.251.5.5 {
		ib-revision 1601284400;
		dynamic;
		hardware ethernet 00:00:00:00:00:00;
		fixed-address 10.251.5.5;
	}
}

This does seem a bit daft, not sure why they have to write them all out if they are just supposed to be static IP reservations (e.g. no MAC address). You could end up with thousands of them, although I'm not sure if has any real impact on the DHCP server.

Paul Roberts
PCN (UK) Ltd

All opinions expressed are my own and not representative of PCN Inc./PCN (UK) Ltd. E&OE
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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Techie
Posts: 12
655     0

Hi Paul,

Yep, thanks, spot on 

For me I see 7 rows for each, for you it's 11 rows in the config file.

 

The Trincic appliances still used DHCPD daemon and I don't know if that discards these upon startup reading the dhcp conf file, hopefully it does so these doesn't written into the lease file so the daemon won't have to search through all of those for every single DHCPDISCOVER.

 

Regardless,

The server has to read through the entire file when starting up and no matter how you turn it there's really no denying a large conf file takes longer to read thus delaying the start of the service. 

 

 

 

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Re: Reserve ip without adding invalid MAC to dhcpd.conf

Expert
Posts: 277
655     0

Well, once the subnet statement has been written out then it's not that many lines for each entry, but yes it will add up over time.

 

subnet 10.251.5.0 netmask 255.255.255.0 {
	ddns-domainname = config-option domain-name;
	ddns-hostname = pick ( option fqdn.hostname, option host-name );
	option host-name = config-option server.ddns-hostname;
	host 10.251.5.5 {
		ib-revision 1601284400;
		dynamic;
		hardware ethernet 00:00:00:00:00:00;
		fixed-address 10.251.5.5;
	}
	host 10.251.5.6 {
		ib-revision 1601287577;
		dynamic;
		hardware ethernet 00:00:00:00:00:00;
		fixed-address 10.251.5.6;
	}
}
Paul Roberts
PCN (UK) Ltd

All opinions expressed are my own and not representative of PCN Inc./PCN (UK) Ltd. E&OE
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