Is there any benefit to setting my own IP address on my little LAN vs. obtain automatically?

I have a little Wired and Wireless LAN at home.  I have cable internet, and the cable modem goes to a Wireless Router (LinkSys) The Router has 4 plugs in the back for Ethernet cables and of course the wireless antenae.  I use 2 desktops that are directly connected to the router via Ethernet, and one Laptop that connects wirelessly.
Me and my wife are the only users.
I like to share everything between the computers and between the two users on each computer.

My question is about in the Network Connections window.  I right-click on the Ethernet Adapter (on the desktops) and the Wireless Adapter (on the laptop)  I choose Properties, then General tab, then TCP/IP out of the list, then Properties. There, I only see the General tab, now, I see Obtain IP Address Automatically is selected (I assume this is as per my installation of Windows XP when I was asked about Internet Connection and chose LAN and Left this settings in) But I want to know if there is any benefit to setting this option to "Use the Followin IP address" and the same for the "Use the Following DNS server addresses"

Now, please don't get too technical, I'm not a network expert.  I Use the LAN basically to pass files between the computers, and share internet access (downloads, P2P, surfing, and email) I would obviously like the fastest settings, and security is a plus.  I just don't know what the difference if any there would be.

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Naser GabajE&P Senior Software SpecialistCommented:
>>I want to know if there is any benefit to setting this option to "Use the Followin IP address" and the same for the "Use the Following DNS server addresses

I hope this will help you undrestand the difference.

Good luck,

Keith AlabasterEnterprise ArchitectCommented:
Personally if you are able to do everything that you want to currently, I would leave it as it is, there is no additonal benefit. ie It won't make things quicker/work better etc.

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Keith AlabasterEnterprise ArchitectCommented:
PS In respect to the differences, I would try to sum it up as follows:

If you have your workstations, the automatic setting may make your work stations change their addresses depending on which machine started up first for example. Do you care? Not in the slightest. However, you may have a program that expects to see a particular work station or server at a specific address all the time. If this was the case, you could select (for that work station) to have a fixed (static) ip address so it would always use that setting for ever.

Your firewall/router is a prime example. You will always have to use the ip address of the router to get to the internet so you don't really want its IP address to be changing every 5 minutes so this will be using a static address.

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I hope this doesn't get too long or complex...

Chances are you won't have anything to worry about in using DHCP (automatic addressing). The computer names will not change if you need to share files with other machines on your LAN, even if the IP changes (which will happen from time to time). Also, it's easier to set up since machines come set that way by default.

With static addressing (your own set IP address), your benefit would mainly pay off if you were running a server of some sort (i.e. mail or web) because you'd ideally want to know that the server can always be found at the same address.

In tems of security, you won't notice a real difference because all of your machines have private IP addresses (i.e. which cannot be seen by the outside world. As long as you have a securely set up wireless network so that outsiders cannot get in, you'll be fine.

Speedwise, there isn't a huge difference... the computers with the static address won't have to contact the router to ask for an IP address when first connecting to the network, where as once that obtain automatically do. Under normal circumstances and to the average user, this time frame is very short. However, having your IP address set will avoid a pitfall of something like the machine not being able to obtain an address from the router (fairly rare, but it can happen).

Letting your machines obtain DNS server info automatically is simpler, but sometimes having DNS information set in the machines will get around DNS server problems in a network (namely in cases where you find your ISP is having DNS problems, like Comcast did for a while last year). It's a good backup, but generally it's fine to let this information get obtained automatically.

So you'll have some slight differences, but nothing that really should adversely affect your experience, based on the information you have provided up with.

Let us know if you need some more detail.
davidgareauAuthor Commented:
Thanks guys, my reason for asking this, is because while I was setting up Shareaza they had a walk through, that said you had to set your IPs to fixed, and enable port forwarding on the Router.

I had Automatic before, and no portforwarding, and I could still share files no problem.
I changed both, hoping to get better file sharing speed, but it seems to have changed nothing speed wise, now I'm confused as to why the Shareaza guide said I had to set it up...

And I'm wondering if I should set it back to like it was before, because at least the port forwarding sounds like it would only be another hole.

The DHCP is another way to say when I select that my IP and DNS servers are automatically set?  Is there an acronym for when they're fixed?

I can see a benefit if some programs expect a fixed IP internally on my LAN, also the not having to look up improving speed makes sense, and lastly the problem with Comcast too... what's the benefit of Automatically Assigning IPs to my internal network if there are these 3 benefits to Specifing the IPs & DNS?


In regard to your DHCP question, yes. In case you're curious, it's short for Dynamic Host Configuration Protocol. There's no acronym for fixed IPs... they're just considered to have static IPs.

Static IPs on the inside pay off when you're using port forwarding. Otherwise, it's possible to forward stuff incorrectly.

It was probably recommended because some people had problems with the file sharing. But if it works fine, don't worry about it. (However, it might be possible that it causes problems for them when they try to look up the files you're sharing) You can set it back to not use forwarding anymore tho.

Using DHCP is essentially simpler... if you ever change settings on the router, the DHCP server will propogate that information out to the machines on the internal network for you when they reconnect to the network. (Routers generally have to restart when you save changes in settings on them)

Hope this helps.
Keith AlabasterEnterprise ArchitectCommented:
I think you will find the reference that they are alluding to is a static IP address on the outside of your routre/cable modem rather than your work stations. The fact that it is already working means you must be alreading performing any necessary forwarding.
davidgareauAuthor Commented:
Hey guys, I'm sorry for the unacceptable delay in answering this thread, I've had to change jobs and this has taken all of my time this past month.

Thanks for the info and ideas.

Keith AlabasterEnterprise ArchitectCommented:
Thanx david
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