DHCP, or Static IP?

[us3rnotfound]

I don't know much about networking, but would it be better to assign each computer on the network using static ip, rather than DHCP? My thinking is since DHCP is just automatically set by the router, that it will just drop the connection more often than if I just set each computer using static IP. Does that make sense?

Thanks.

 

[Subzero]

From what I have learned in the last week you do not want to use a static,go with DCHP ..

 

[TechnoPro]

Originally posted by: shminu
I don't know much about networking, but would it be better to assign each computer on the network using static ip, rather than DHCP? My thinking is since DHCP is just automatically set by the router, that it will just drop the connection more often than if I just set each computer using static IP. Does that make sense?

Thanks.

DHCP is the way to go, unless you have a specific need for a static IP on one of your machines (a web server or file server, etc). Your thinking about the connection dropping more frequently with DHCP is incorrect.

 

[Nothinman]

DHCP will have no affect on the connectivity, unless you employ some IP-based rule sets and even that can be worked around by using DHCP reservations to ensure a certain host always gets the same address. All DHCP does is save you time and hassel by configuring all the clients automatically, the only time I would not consider using it is if there was less than around 5 machines to configure. I only have 4 machines at home (one being the DHCP server) and all of them are autoconfigured, it's great because I can plugin a laptop, reload a machine, install something in VMWare, etc and IP connectivity just magically works.

 

[cmetz]

shminu, static is more reliable, because once you set it up, you're done. Static also requires more human administration overhead - you have to configure each client, and if you do it wrong, you'll spend time debugging it, and if you change something, you have to make sure you update every client. DHCP vs. static is a trade-off, but DHCP's popularity says that a lot of people decide that the ease of administration beats the potential for problems.

 

[Nothinman]

Your post contains conflicting information. It would seem reasonable that since you setup DHCP once and then it applies to all clients it would be more reliable since there's less chance for human error.

 

[TechnoPro]

Originally posted by: cmetz
shminu, static is more reliable, because once you set it up, you're done. Static also requires more human administration overhead - you have to configure each client, and if you do it wrong, you'll spend time debugging it, and if you change something, you have to make sure you update every client. DHCP vs. static is a trade-off, but DHCP's popularity says that a lot of people decide that the ease of administration beats the potential for problems.

Cmetz, if I may pick your brains a bit because you explain these things well...

You say that "static is more reliable". Reliable in what respect? Obviously, it eliminates DHCP server failure and/or errors as a potential problem, but what else about it is inherently more reliable? I guess I am looking at it very simplistically: either a human manually configures the client, or a DHCP server configures the client (or more accurately provides the data for the client to configure itself...). Either way there is a margin for error/failure.

Enlighten me, please.

 

[gunrunnerjohn]

IMO, there is no reason for the typical home user to go with static IP addresses, especially since most SOHO routers allow you to lock the IP address issued by the DHCP server to a specific hardware MAC address. This allows "static" IP addresses that are still administered from a single point, the router's configuration page. I have to disagree that static IP is less reliable, there should be no measurable difference in the reliability between the two methods. A strike against static is as the network gets bigger, it's easy to have a duplicate IP address, especially if all devices aren't on 100% of the time, and it takes time to track it down. DHCP avoids that issue, not to mention it's MUCH easier to manage.

 

[cmetz]

TechnoPro, DHCP introduces new failure modes. Your DHCP server needs to work reliably, for example, which creates a lot of potential failure modes - what happens if your DHCP server is slow, and sometimes doesn't work but usually does? And there must not be another system on the network that is misconfigured to be a DHCP server (as deployed, DHCP has no security). And possibly this requires new local firewall configuration. And some OSs made near Seattle do sundry internal networking things a little differently with DHCP - new code paths.

All these failure modes add up to new ways for things not to work that won't be there with a static IP address, and thusly your network WILL be less reliable. So the question is: how much trouble do these problems cause, and how much other benefit (ease of administration) do you gain by doing it? Typically, once you get DHCP running it mostly stays that way for a while, so the trouble isn't much, but when you need to reconfigure your network and/or add new hosts, the ease of use pays off. So typically it's a good trade. But not always. For example, in a data center environment where we're talking about important servers, DHCP is unacceptable - even the small reliability hit is just too much.

 

[Xtremist]

I'll add my 2 ¢ in the picture. DHCP may have some reliability issues, particularly at the server application level. If the DHCP doesn't respond, you're screwed. People have pointed out and I think it's a big factor personally, that defining IP's statically in the OS config (since DHCP essentially allows you to statically define/allocate IP's to machines as well) can lead to real big issues. I'll admit that on more than one occasion I've brought up old servers on our network and when the network stack loads you get an IP conflict (assuming you've kept the same IP for the new server) which has very unpredictable errors. This can be worse than not getting an IP at boot-time and then having to restart your DHCP service/server.

Personally I used to be a strictly static guy. But I've switched to the DHCP camp. It's just so much easier. Nothing's better than having a lan party and just telling the freak who's pumped up to help choose an IP range and configure everyone's PC, to just sit down, set it to DHCP and CHILL!

 

[chsh1ca]

DHCP *CAN* assign static IP addresses, provided the DHCP server can support it. DHCP is not really just about configuring IP addresses, it is more about configuring everything you need for that host (hence the name: Dynamic Host Configuration Protocol). On a large network, it can be cumbersome to have to modify various server addresses (DNS, WINS, etc) on every single machine, and this is overcome simply with DHCP.

For a small network with a router appliance that handles DHCP, I'd definitely do DHCP.

 

[TechnoPro]

Originally posted by: chsh1ca
DHCP *CAN* assign static IP addresses, provided the DHCP server can support it. DHCP is not really just about configuring IP addresses, it is more about configuring everything you need for that host (hence the name: Dynamic Host Control Protocol). On a large network, it can be cumbersome to have to modify various server addresses (DNS, WINS, etc) on every single machine, and this is overcome simply with DHCP.

For a small network with a router appliance that handles DHCP, I'd definitely do DHCP.

Not to pick here, but the more common definition of DHCP is Dynamic Host Configuration Protocol. Although Google did show me that your answer was valid as well.

 

[chsh1ca]

Originally posted by: TechnoPro
Not to pick here, but the more common definition of DHCP is Dynamic Host Configuration Protocol. Although Google did show me that your answer was valid as well.

Actually, I generally refer to it as such, but I blame it being late when I wrote the message. I edited it for correctness.

 

[gunrunnerjohn]

I was obviously addressing the actual situation being discussed in this thread when I was talking about DHCP reliability, that being a broadband router and a home network. IMO you'd be hard pressed to come up with a difference in reliability between DHCP and static IP addresses in that environment, and DHCP is a whole lot easier for the novice to get running, since it's the default configuration for most O/S installations.

But not always. For example, in a data center environment where we're talking about important servers, DHCP is unacceptable - even the small reliability hit is just too much.

First off, servers are rarely configured to use DHCP, but a vast majority of the Fortune 500 company's networks use DHCP for most of the machine, so I guess they've learned to live with the "unreliability" problems.

I've worked with a few large companies in the Phila area, and I've yet to come across a corporate network that doesn't use DHCP for the workstations, and I'll be somewhat surprised if I ever do...

 

[Calin]

We have a Windows XP system with Internet Connection Sharing and DHCP server, and sometime (once a month or so) the DHCP part just stops working. I am glad I have a static assigned IP address

Calin

 

[Nothinman]

We have a Windows XP system with Internet Connection Sharing and DHCP server, and sometime (once a month or so) the DHCP part just stops working. I am glad I have a static assigned IP address

Call me crazy but I don't think XP+ICS is considered a high-availability option. I have a Linux box doing NAT and another doing DHCP/DNS and I never have a problem.

 

[gunrunnerjohn]

I have a bunch of systems running on a D-Link DI-614+ router, including my TiVo and a Linux box. I can't remember ever having a DHCP issue, and the network is rock-solid. I've installed a bunch of small networks for local businesses, and all of them use DHCP without any issues. I really don't know where the claimed reliability issue with DHCP is coming from...

 

[Xtremist]

Originally posted by: Nothinman

We have a Windows XP system with Internet Connection Sharing and DHCP server, and sometime (once a month or so) the DHCP part just stops working. I am glad I have a static assigned IP address

Call me crazy but I don't think XP+ICS is considered a high-availability option. I have a Linux box doing NAT and another doing DHCP/DNS and I never have a problem.

Window's DHCP server is pretty reliable too. I've worked in my new department for 6 months now and we've never had any problems with it. I think we rebooted the server once (unrelated issue as the server is domain controller too).

 

[Nothinman]

Window's DHCP server is pretty reliable too. I've worked in my new department for 6 months now and we've never had any problems with it. I think we rebooted the server once (unrelated issue as the server is domain controller too).

The mini-DHCP server built into XP? Even though I don't doubt it can run without too many problems, I wouldn't try it in a real environment since you can't even change the f'ing range it hands out.

 

[Xtremist]

The mini-DHCP server built into XP? Even though I don't doubt it can run without too many problems, I wouldn't try it in a real environment since you can't even change the f'ing range it hands out.

No, I wasn't referring to Windows XP. I don't believe Windows XP can serve as a domain controller?

 

[gunrunnerjohn]

I wasn't aware that XP had any sort of DHCP server capability, where does that appear?

 

[Xtremist]

Originally posted by: gunrunnerjohn
I wasn't aware that XP had any sort of DHCP server capability, where does that appear?

I don't actually know either, although I guess it could make sense that the Connection Sharing would handle IP allocation. Honestly I've never even used Connection Sharing in any version of Windows, but that's what I'd assume is going on?

 

[Iron Woode]

Originally posted by: Xtremist

Originally posted by: gunrunnerjohn
I wasn't aware that XP had any sort of DHCP server capability, where does that appear?

I don't actually know either, although I guess it could make sense that the Connection Sharing would handle IP allocation. Honestly I've never even used Connection Sharing in any version of Windows, but that's what I'd assume is going on?

Yup, WinXP ICS has a mini DHCP server.

Personally I use Freesco on an old PC and it handles everything like a champ.

 

[Diaonic]

DHCP is the way to go, I use static ips for my servers an network printers,firewall ect...

 

[Nothinman]

No, I wasn't referring to Windows XP. I don't believe Windows XP can serve as a domain controller?

No, but the post I was replying to was using XP+ICS. But I'm not a fan of MS so I wouldn't use their DHCP server unless I had absolutely no other choice.