DHCP assigning strange IP addresses

[Kanati]

Um, okay?

I agree with Fordem but I'm sure Maninpc hasn't carried all his devices out to the bookstore cafe'...which is why I said the router is assigning these addresses randomly because of the way it is programmed. Yes it is possible for a PC to carry with it a previously assigned address, yes it is possible for devices to get that same address or the next available but if there were no other reason for PCs to get the next available address, starting with the first numerically available within the DHCP address range...then what could it be? (1) Either the router is programmed to do this in this manner or (2) People outside the router are hopping on and surfing or (3) Address reservation has already been used for that device. If it is the router programming, nothing can be done but new firmware. If it is people hopping on, then Maninpc can see this under "Attached Devices" and then he needs to setup some better security. If it is Address Reservation, he can simply change the addresses to be in numerical order...either starting with the first available in the address range or number each/some/all devices outside the address range. Either way will work. I recommend using Address Reservation.

[Mars Mug]

Simply powering off the router and PCs then powering on again will clear most of those possible issues.

By the way I've never seen a Netgear router randomly issuing IP addresses from the DHCP pool, and my '3700 doesn't.

[Kanati]

Yes, power cycling devices should clear the issue...it does with other routers. But with this router, it works 'some' of the time.

I can't explain why, but my WNDR3700 does randomly assign addresses. Atleast, it did before I started using DHCP Reservation. Other routers I've owned did not have this behavior.

[maninpc]

Thanks all for your input, However in my past experience a DHCP router assigns ip address in synchronized order. 192.X.X.2, then next device would get 192.x.x.3, and so on. I have never seen a dhcp router just throw out any random number like i am getting.

[Mars Mug]

Originally Posted by Kanati

I can't explain why, but my WNDR3700 does randomly assign addresses. Atleast, it did before I started using DHCP Reservation. Other routers I've owned did not have this behavior.

I'm not suggesting that you are lying or are wrong, just saying that I have not seen this happening, I don't deny the possibility.

It might be a good idea to power off the router/PC just to clear the tables so that we get a fresh start.

It might also be a good idea to run a network scanner to scan the subnet (e.g. 192.168.1.1 to 192.168.1.254) and see what's there, I use this one;

http://www.softperfect.com/products/networkscanner/

[fordem]

Originally Posted by maninpc

Thanks all for your input, However in my past experience a DHCP router assigns ip address in synchronized order. 192.X.X.2, then next device would get 192.x.x.3, and so on. I have never seen a dhcp router just throw out any random number like i am getting.

I'm not certain if you read my earlier post - the point I made there was that whilst most DHCP servers will issue addresses sequentially, there are many factors that can affect this and it is neither abnormal nor incorrect for the server to isses addresses out of sequence.

It is not a failure of the unit, and your never having seen it happen, doesn't change that - if you want specific addresses you must either assign static addresses or use DHCP reservation.

[jmizoguchi]

Originally Posted by maninpc

Thanks all for your input, However in my past experience a DHCP router assigns ip address in synchronized order. 192.X.X.2, then next device would get 192.x.x.3, and so on. I have never seen a dhcp router just throw out any random number like i am getting.

if router is setup to use 192.168.1.2~192.168.1.254/ 255.255.255.0 , DHCP will not randomly pushes other LAN subnet as such as 192.168.0.x to DHCP client .

[Kanati]

I'm not suggesting that you are lying or are wrong

I didn't think that you were Mars.

It is not a failure of the unit, and your never having seen it happen, doesn't change that - if you want specific addresses you must either assign static addresses or use DHCP reservation.

Agree completely Fordem, well said.

Thanks all for your input, However in my past experience a DHCP router assigns ip address in synchronized order.

You are welcome and I too have experienced the same thing with other routers. IMO it isn't a serious issue. As Fordem explains, use DHCP Reservation or statically assign addresses if it bothers you to have non-sequenced addresses.

[Kanati]

if router is setup to use 192.168.1.2~192.168.1.254/ 255.255.255.0 , DHCP will not randomly pushes other LAN subnet as such as 192.168.0.x to DHCP client

Absolutely right...did somebody say that?

Maninpc said

the DHCP server now assigns IP addresses in a new range. Example. DHCP range is set to 192.168.1.2 to 192.168.1.254. We use to get IP assigned to my laptop 192.168.1.2, Now, it's being assighned 129.168.1.44

So it isn't in a new range...it's in the same range, just out of order or not starting at 192.168.1.2. It isn't jumping into a new subnet like 192.168.0.2. Right?

[jmizoguchi]

Originally Posted by Kanati

Absolutely right...did somebody say that?

Maninpc said So it isn't in a new range...it's in the same range, just out of order or not starting at 192.168.1.2. It isn't jumping into a new subnet like 192.168.0.2. Right?

Now, it's being assighned 129.168.1.44

seems like it was miss type by the user. 192.168.1.44 is what user meant