Easy question about IP addresses

Who assigns 'em? Specifically, if you buy a NAS (network attached storage device), do you have to assign it an IP address to stick it on your network, or does it come with one?

Athena, who is very, very smart about some aspects of computers and very, very dumb about others.

How big is your network? What address range do other machines on your local network fall into? Does this device need to communicate with computers outside your local network?

You can probably just assign it an address in the 10.x.x.x or 192.168.x.x range. These are reserved for private networks and do not need to be purchased.

Thanks, Number. This is a theoretical question, not a real live need. Would it be true to say that a network administrator generally assigns IP addresses? (as opposed to them coming with a device, or purchasing them).

While they don’t really assign them as much as they coordinate their assignment, ICANN is responsible for giving out IP address blocks, not individual addresses. The blocks are assigned in three different types, Class A (rarely, in fact I think they are all, or almost all, spoken for), Class B, and Class C.

The following are approximate sizes of each block types:

Class A - 16 million addresses
Class B - 65 thousand addresses
Class C - 254 addresses

Except for extremely large corporations (think ATT), most companies either get Class B or Class C blocks. Sometimes these blocks will be broken down further with subnet masks, but you get the general idea.

To answer your second question, the attached storage will not have a pre-assigned IP address, so it will be assigned by the IT personnel in the company. There’s also the possibility of DHCP, in which case the network software assigns the IP address, but that’s possibly getting more technical than you wanted me to.

Whoever assigns IP addresses for your network should assign one for the device. Your device may come with a default IP address already programmed into it, but this may interfere with your network.

Here’s 2 examples:

(1) At home, I have an internet connection, and I also have my own private network (yes, I’m a computer weenie with about 20 computers on my own little network). All of my local addresses are 192.168.0.x where x is the unique number for the computer. It is up to me to make sure that any new devices I stick on this network conform to this numbering scheme. The internet connection uses DHCP to obtain an IP address from my internet provider. Since I only get 1 IP address from them, I have to make sure that I only have one connection to the ineternet.

(2) At work, I don’t control the network assignments. If I just hook up a piece of equipment with a 192.160.0.x numberig scheme then I’m going to muck with certain pieces of equipment on our network. I have to go to the IT group and tell them I need an IP address, and they give me one (or more often I just give them the device and they program the correct IP address into it).

These are only two of a wide variety of scenarios, so the simple answer is of course to go see your network administrator. If you are doing this at home on a small home network, then you are the network administrator!

Hmmm… I see after hitting submit that a few other people have answered as well.

I’ve never bought a NAS, but I’ve had quite a few pieces of equipment come in programmed to YMMV.

I just recently found this really neat computer help website here in Toronto. It has been right under my nose all the time and never knew about it.

As a big bonus it uses the same message board system as straight dope and you get answers just as quick.

Here’s the link…


if you search for it manually remember it is


you have to include the word “THE”


Actually, for a variety of reasons, most large organizations are avoiding assigning static (i.e., permanent) IP addresses to computers. Instead, they use DHCP to assign an address as needed.

But they wouldn’t be assigning a dynamic IP to a NAS, since it is device that provides services for other computers. Making it a moving target wouldn’t be the wisest course of action.

Actually the class system has largely been replaced, since it just isn’t flexible enough.

The “classless” network system describes networks in terms of netmasks such as a “/24” (same size as a Class C) or a “/16” (same size as a Class B). This, above all other things, allows very impractical Class A and Class B ranges to be allocated in more useful subsets (such as a /20 – equivalent to 16 Class Cs).

Dynamic DNS avoids this problem quite nicely. It’s been available with Netware for about three years now, and I know that it is also available with Linux and BSD as well. I have no idea if it can be done with a Microsoft OS (and I hope I never have to find out :p).

“Dynamic DNS avoids this problem quite nicely.” – tourbot

I don’t think I would agree with the word “nicely”. :slight_smile:

Dynamic DNS is better designed to allow workstations and the like to have persistent hostnames. Actual servers are not generally given dynamic DNS since DNS is by its nature designed to run with significant record cache times.

And of course DNS resolution accessing a shared mount occurs at attachment time, so keeping the same IP address gives clients a fighting chance not to have dead mounts after the NAS is cycled.

Ok, “nicely” may be overstating the case. I was thinking in terms of what’s possible. What’s practical will vary from situation to situation.

I can’t parse this sentence. It sounds like you are saying that DNS resolution is accessing a shared mount, and I’m sure that isn’t what you meant. But your concern that the NAS (or any other server’s) IP will be released and renewed while a client is connected is definitely a good reason why a static IP is better in most cases. I know of people who run web servers with dynamic IP addresses. For non-critical applications where no other choice is available… well, it works. :slight_smile:

Sorry. Lemme rephrase that horrid statement.

Instead of “DNS resolution accessing a shared mount occurs at attachment time”, lets say

In the process of accessing a network-shared disk mount, the file server’s IP is resolved from DNS when the system is in the process of attaching to the mount. Yes, as you guessed, the point I was over-hastily trying to make was that once the attachment is made, the connection is based on IP until the attachment is released, so if the IP address changes, all attached mounts go stale.


You’re correct that IP addresses are usually pre-assigned on network devices, as very few come loaded with a null value (although some do seem to default to I should have stated that the devices are not pre-assigned with the IP address that they will be using in the real world.

Undead Dude,

I did gloss over the Class issue briefly when I mentioned subnet masks, but I wasn’t trying to get too technical. I also didn’t go into depth about DHCP and didn’t even touch on IPv6, since I didn’t think those were germain to the OP’s question.

In case anyone wants the technical details on the subjects that we glossed over, check out IPv6 and DHCP.

hehehehe, you guys are great. All I wanted was to be able to say “An IP address is assigned by the network administrator” with a reasonable assurance that I wasn’t outright lying, and now I have more info about IP addresses than I ever wanted to know! Viva Straight Dope!