The strange IP address

I beg someone to look at my question, please.

If the NIC card is down or some other problems on the ISP's side, you can't get the connection to the Internet.

However, your system gives you an IP address. What is it?

How does it give you this address?

I know the CSMA/CD aspects on the Ethernet.Linuxquestions.org

I fail to understand exactly what your asking?

Some operating systems when you lose an IP address, they will default to a 169.x.x.x type address, not sure if that's what your looking for but then again, your question really didn't make a whole lot of sense to me. Are you wondering about this in Linux or another OS?

Could even be 127.0.0.1 - the loopback address.

I thank both of you for the replies

I am studying a course on Data communication. We study LAN aspects, subnetting, repeaters, hubs, switches, routers, routed protocols, roting protocols, etc.
[Now I know a lot about subnetting; only in IPV4.]

My teacher touched on this topic. Unfortunately, I forgot to write down that particular IP address. If you can't log on to the system, there is a standard IP address which will automatically given by your system or probably the NIC card.

What is that address?
If you know networking, you ought to know this.

My teacher works with Windows based systems. I don't work with Windows. I have Mandriva Linux 2006 version


It is not the loopback address. I am pretty sure.

Just pull your ethernet cable out of your nic and do a dhcp request en your will get that ip. As far as i can remember it starts with 169.x.x.x

So yeah, with Windows it defaults to a 169.x.x.x address like I previously stated. In Linux, it usually doesn't do this and will either just fail claiming the old previous IP or eth will just show up with no IP.

http://www.tcpipguide.com/free/t_DHC...ddressingA.htm

Because this isn't a Linux question I have moved it to General.

169.254.x.x addresses are reserved, i.e. do not exist on the internet. They are defined as "link local" addresses, that is addresses that can be auto-assigned to an interface for local communication, but obviously you can't expect to communicate off-network as 169.254.0.0 doesn't actually exist in any one place. The second two digits are normally generated from the mac address using an algorithm that I can't recall.

Check out RFC 1700, Assigned Numbers

Thanks baldy

As far as I have learnt the following are the bunch of private addresses in IPV4 system.

10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

So the address 169.254.x.y. is not inside the above range. It can't be a reserved one.

I'm afraid it a bit more complicated than that. 169.254.x.x are indeed reserved as are others. I suggest you look at RFC 1700 for the full story

Does this help at all?

Some of the facts are murky. I mean people don't talk much about some facts.

The RFC's are the facts. The use of 169.254.x.x addresses as auto-assigned addresses is purely optional. Microsoft do it, although its a bit twitchy most of the time. I don't think Linux does, but frankly I've never found it helpfull anyway.

Originally Posted by Gins I thank both of you for the replies I am studying a course on Data communication. We study LAN aspects, subnetting, repeaters, hubs, switches, routers, routed protocols, roting protocols, etc. [Now I know a lot about subnetting; only in IPV4.] My teacher touched on this topic. Unfortunately, I forgot to write down that particular IP address. If you can't log on to the system, there is a standard IP address which will automatically given by your system or probably the NIC card. What is that address? If you know networking, you ought to know this. My teacher works with Windows based systems. I don't work with Windows. I have Mandriva Linux 2006 version It is not the loopback address. I am pretty sure.

So in other words, you're asking us to do your homework for you.