Questions about Static IP addresses

[Kaido]

I have a couple questions about Static IP addresses:

1. Assuming that the router is running DHCP and you set Computer A to have a Static IP of 192.168.1.100 (set locally on the machine in the TCP/IP settings), what if you shut it down for a few minutes, and in that few minutes Computer B boots up on the network and grabs 192.168.1.100 while Computer A is offline, and then Computer A boots back up wanting to jump on 192.168.1.100? Will it kick Computer B off? Will it create a conflict that isn't resolved until you repair Computer B's connection?

2. My new work router has the ability to set Static IP on itself. Do I have to set a corresponding Static IP in the TCP/IP settings of the computer that I want to have that Static IP? Or do I only have to set it once, on the router itself?

 

[n0cmonkey]

1. IP Conflict. I don't think either machine would work properly. Solution: Don't set static ip addresses within the DHCP range.

 

[JackMDS]

Concerning DHCP and Static IP.

In general, there are two kinds of Entry Level Routers.

1. The Router cannot reserve a Static IP within the DHCP (aka as Static DHCP).

When using such a Router you have to make sure that you are assigning Static IP out side of the DHCP range, and the TCP/IP stack has to be configured with the actual Static IP.

2. Router that can reserve an IP within the DHCP range.

When using such setting the TCP/IP on the computer stays on Obtain Auto.

The Router would have a menu that usually would allows you enter the MAC number of a specific computer to be associated with a specific IP.

If the number of computers is always the same and there enough IPs in the DHCP, stealing should not occur.

To avoid IP "stealing" on a flexible size Network, make the DHCP range large enough so that there are available IPs that are not reserved.

Keep in mind that the implementation of Reserved IP on Entry Level Routers is not a real standard and might be implemented differently depending on the Make and Model.

 

[marulee]

Originally posted by: n0cmonkey
1. IP Conflict. I don't think either machine would work properly. Solution: Don't set static ip addresses within the DHCP range.

Fair enough!

Change the range from the router to avoid the hassle!

'LIfe is cool'

 

[Kaido]

Okay, so my range is 192.168.1.100 - 192.168.1.149 - am I safe setting Computer A to 192.168.1.150 as static because (1) it's outside the DHCP range but (2) within the same Subnet?

 

[n0cmonkey]

Yep, anything above 149 and below 100 (excluding addresses already in use) should be safe.

 

[Slowlearner]

In a small local area network is it better to have static IPs or DHCP? I was under the impression that DHCP provided an additional layer of protection, may be a minor one. However I have found static IPs generally result in more stable network connections, and sometimes required by database software.

 

[RebateMonger]

There should be no functional differences for client PCs whether they are using Static or Dynamic IP addresses.

DHCP clients attempt to renew their IP addresses from the DHCP Server when they reach 1/2 their lease term. If the network and the Server are functioning properly, they receive a new lease and go on with life. It happens very fast and, depending on the lease term, may only happen once every day or two or three.

Servers are typically given Static IP addresses and client PCs are typically given Dynamic IP addresses. The self-management ability of the DHCP system makes IP management much easier and is the recommended method for client PCs unless there's a specific reason to not use DHCP on a particular client.

 

[Kaido]

Originally posted by: RebateMonger
There should be no functional differences for client PCs whether they are using Static or Dynamic IP addresses.

DHCP clients attempt to renew their IP addresses from the DHCP Server when they reach 1/2 their lease term. If the network and the Server are functioning properly, they receive a new lease and go on with life. It happens very fast and, depending on the lease term, may only happen once every day or two or three.

Servers are typically given Static IP addresses and client PCs are typically given Dynamic IP addresses. The self-management ability of the DHCP system makes IP management much easier and is the recommended method for client PCs unless there's a specific reason to not use DHCP on a particular client.

Yup...we just installed a Small Business Server 2003 server and it requires a Static IP.

 

[spidey07]

Originally posted by: Kaido
Yup...we just installed a Small Business Server 2003 server and it requires a Static IP.

All server ip addresses should be static.

 

[marulee]

Originally posted by: RebateMonger
There should be no functional differences for client PCs whether they are using Static or Dynamic IP addresses.

DHCP clients attempt to renew their IP addresses from the DHCP Server when they reach 1/2 their lease term. If the network and the Server are functioning properly, they receive a new lease and go on with life. It happens very fast and, depending on the lease term, may only happen once every day or two or three.

Servers are typically given Static IP addresses and client PCs are typically given Dynamic IP addresses. The self-management ability of the DHCP system makes IP management much easier and is the recommended method for client PCs unless there's a specific reason to not use DHCP on a particular client.

Fair enough!

Just for your reference, for small networks IP should be 192.0.1.x to 223.255.254.x, and subnet should be 255.255.255.0.

 

[n0cmonkey]

Originally posted by: marulee
Fair enough!

Just for your reference, for small networks IP should be 192.0.1.x to 223.255.254.x, and subnet should be 255.255.255.0.

That's probably a bad idea.

 

[InlineFive]

Originally posted by: marulee

Originally posted by: RebateMonger
There should be no functional differences for client PCs whether they are using Static or Dynamic IP addresses.

DHCP clients attempt to renew their IP addresses from the DHCP Server when they reach 1/2 their lease term. If the network and the Server are functioning properly, they receive a new lease and go on with life. It happens very fast and, depending on the lease term, may only happen once every day or two or three.

Servers are typically given Static IP addresses and client PCs are typically given Dynamic IP addresses. The self-management ability of the DHCP system makes IP management much easier and is the recommended method for client PCs unless there's a specific reason to not use DHCP on a particular client.

Fair enough!

Just for your reference, for small networks IP should be 192.0.1.x to 223.255.254.x, and subnet should be 255.255.255.0.

Actually, there are three private IP ranges of which Kaido could use. The 192.168.x.x range is the most widely known of because most SOHO manufacturers ship their devices with that range preconfigured.

10.0.0.0-10.255.255.255
172.16.0.0-172.31.255.255
192.168.0.0-192.168.255.255

It doesn't matter which one is chosen.

 

[nweaver]

Originally posted by: marulee

Originally posted by: RebateMonger
There should be no functional differences for client PCs whether they are using Static or Dynamic IP addresses.

DHCP clients attempt to renew their IP addresses from the DHCP Server when they reach 1/2 their lease term. If the network and the Server are functioning properly, they receive a new lease and go on with life. It happens very fast and, depending on the lease term, may only happen once every day or two or three.

Servers are typically given Static IP addresses and client PCs are typically given Dynamic IP addresses. The self-management ability of the DHCP system makes IP management much easier and is the recommended method for client PCs unless there's a specific reason to not use DHCP on a particular client.

Fair enough!

Just for your reference, for small networks IP should be 192.0.1.x to 223.255.254.x, and subnet should be 255.255.255.0.

holy crap....where do you get this stuff? I'm trying not to be rude, but....

 

[spidey07]

Originally posted by: nweaver

holy crap....where do you get this stuff? I'm trying not to be rude, but....

I got a chuckle from the posts as well.