D-Link Forums

D-Link VPN Router => DSR-250N => Topic started by: ekimla on December 20, 2013, 10:13:43 PM

Title: Reserved IP Addresses
Post by: ekimla on December 20, 2013, 10:13:43 PM

I'm no IT expert but one thing I have found useful in the management of my home-business network is to keep a record of my static IP devices in a chart.  I believe that this chart is most conveniently viewed/accessed within the DHCP server (DSR-250N).  Therefore I like to make use of the DHCP Reserved IPs feature to chart this out.  Unfortunately, for whatever reason, certain devices just don't work fully/properly unless I configure a static address within the device (for example the DNS-323 won't send emails if you leave it to a DHCP, even though it gets a constant reserved ("static") IP handout).

1) I'm curious to know how other people handle this static-IP-device record-keeping
2) Why is it that some devices must have static addresses set locally on the device?  Doesn't DHCP reservation accomplish the same thing?

3) I just tried to change my DHCP Domain Name and got an error that my DHCP IP reservations were now outside of range of my DHCP.  I just upgraded to the 1.08B39 firmware, so perhaps this was a "fix" because as I now understand, DHCP reservations must be within the DHCP range.  Unfortunately though, I now can't use the DHCP reservations feature to do charting in the router, since I think I want my static IPs OUTSIDE the DHCP range - I understand that this is better design and avoids addressing conflicts.  Somehow I've been "getting away" with doing it wrong for all this time.  What is the "pro" way to handle all this?
Title: Re: Reserved IP Addresses
Post by: FurryNutz on December 21, 2013, 10:18:01 AM
It's recommended to let the router handle ALL IP reservations and to make reservations ON the router for all devices in your building and this is a preferred method instead of using static IPs. Let the router keep the central location for IPs since it's what it's designed to do.

You can have some devcies outside the DHCP pool and set for static, items like Wireless APs or NAS can reside out side the pool if no router management is needed, i.e. QoS.

Title: Re: Reserved IP Addresses
Post by: ekimla on December 22, 2013, 06:36:49 PM
Thanks for the tips.  I guess there is no way then of limiting the dhcp address handouts so that the static IP reservations are not in the dhcp range.
Title: Re: Reserved IP Addresses
Post by: FurryNutz on December 23, 2013, 11:13:50 AM
You have to remember that Static IP is different from Reserved IP. Reserved is managed and controlled on the router with in the give DHCP IP address pool. Static IP is an IP address manually input by a user on the device connecting to the router, it can be with in the DHCP IP address pool or outside the pool. Out side the pool is preferred for Static IP addresses.

DCHP IP Pool - (Reserved IP addresses for devices are managed by the router in this pool.)

Static IP address outside the pool - or
Title: Re: Reserved IP Addresses
Post by: ekimla on December 29, 2013, 06:17:17 AM
I'm just going to provide a little clarification:

My understanding is that using the "reserved ip addresses" method or "static ip" method  accomplish the same thing:  a consistent address to reach a network device.  So they do the same thing, just in a different way.

Ultimately I'd like to have this result:

Reserved/static addresses outside of a range of dynamic dhcp server addresses.

For example:

Static addresses below 10.  reserved addresses between 11-50 with some voids in this range for future devices. Dynamic addresses between 100-150.

This allows you to quickly identify the device type simply through the address itself.
Title: Re: Reserved IP Addresses
Post by: ekimla on January 03, 2014, 07:47:47 AM

I don't know how I missed the option to create the DHCP reserved IP pool.  Just found the option below and I believe this will separate the addresses as I want.  Thanks FurryNutz and sorry for the silly question!
Title: Re: Reserved IP Addresses
Post by: ekimla on January 03, 2014, 09:03:37 AM

Ok another stumbling block:

In the DHCP reservations section, you can create individual DHCP IP reservations based on MAC addresses. 

What is this check mark option: "Associate with IP / MAC Binding"??

Also, there is an option for DHCP ReservedIP Pools.
My understanding is that the ReservedIP pool must be within the standard DHCP IP Pool?
Does this Reserved IP Pool then prevent the DHCP server from handing out addresses in the Reserved Pool range?
Title: Re: Reserved IP Addresses
Post by: FurryNutz on January 10, 2014, 08:39:24 AM
I presume that the Associate with IP / MAC Binding is for just that, a particular MAC address is bound and associated with an IP you reserve for that MAC address...

I presume that the Reserved IP address pool would be with in the DHCP IP pool...

I would think that the Reserved IP Pool would not prevent the server for handing out IPs in the same range...it should be handing out what has been assigned to devices and also Dynamically hand out IPs to those which have not been Reserved and assigned.