use static or DHCP?

[Christine Hartman]

I would like to know what most people use as "best practices" for servers in their data centers. Do they hardcode their ip address on their servers or do they DHCP (manual or Dynamic)? I am looking for what the industry uses more.

[Pete Randall]

Static.


Pete

[Rita C Workman]

Servers - static

Network Printers - static

Client PC's - DHCP (with very few exceptions)

Our general standard here...

Rgrds,
Rita

[Patrick Wallek · Accepted solution]

Definitely static hardcoded.

Would you want the possibility of having a servers IP address change and then have applications stop working and people unable to access the server? I wouldn't!

[Geoff Wild]

Static for servers and DHCP for clients - unless clients need to be in a vpn/secure network...

Rgds...Geoff

[Christine Hartman]

thanks for the quick response. I am trying to make a case to use static IPs here for our servers...one of the network admins. are trying to force us to use M-DHCP for our servers. He has not given any compelling reasons 'Why'. If you have any reasons to help my case please let me know. Again thanks so much.

[Pete Randall]

The best reason I can think of is "why introduce unnecessary complexity?". I prefer the KISS method: Keep It Simple Stupid. That way, when you do have problems, there's one less layer to debug.


Pete

[Patrick Wallek]

See my response above -- If the IP of a server changes, chances are good that applications will BREAK!

[Kelli Ward]

One compelling reason not to use DHCP for say a printer or a server is:
How can your workstations ensure access to that server or printer, if it loses it's lease and obtains another with a different address?

BTW - We use almost exclusive static IP's here.

I have a thought, maybe your admin can make his DHCP server, it's client as well, wouldn't that solve everything? ;)

Good luck,
Kel

[Geoff Wild]

Plus - if they are using Micro$oft DNS with Allow Updates? - then watch out for DHCP hijacking - search Google for more info on this - we ran into that at our site - not because it was intentional - but because MS DHCP server don't clean up their PTR records when they update DNS....

[John Dvorchak]

Netjerk guys...Where do they come from? I think I would get a piece of paper and write in big letters "CLUE" on it. Then take it to the next meeting with the network admin and hold it up. Ask him if he has one of these.

But that is just my humble opinion.

[John Poff]

Hi,

Our network guys use DHCP for all the desktop and laptop Windows machines, and even the Windows servers, but for our Unix boxes we use all static IP addresses.

It's a minor issue if my laptop picks up a new IP address, but it would be a real headache to several hundred users if the big rp8400 running Oracle Financials in our MC/SG cluster suddenly got a new IP address. :)

JP

[Christine Hartman]

our DHCP server is on HPUX but will move to linux. Curious...how about static ip-ing linux servers and windows servers? There are some windows servers that run important applications too and email. The NT group has been battling this argument for a while now..because all of their stuff DHCPs. Now that they are implementing Active Directory they at times run into major network connectivity issues. I'm in the unix group and we have NEVER had to DHCP our servers in the past. It would be nice to push to standardize on ALL servers regardless of platform. Desktops and printers I'm not so worried about, but servers definately!

[Tony Contratto]

Our setup is the same as many have already stated:

Servers - Static
Clients - DHCP

If the network guy still insists on all servers being DHCP, I would suggest that you start with the DHCP and DNS servers first. Then, after you get those working, continue on to the others. :)

--
Tony

[Kelli Ward]

Hi,
I agree with Anthony.

If you're going to use DHCP at all and want standardization:

Servers - static
Workstations and desktops - DHCP

You just don't need the headaches of this server this way, that server the other and then tracking it all.

Good luck,
Kel

[Rita C Workman]

I didn't read every response...but why would you want to have servers set to static, as opposed to the DHCP the other guy wants?

Patrick mentions it...you will more than likely affect applications. Remember, alot of software gets its licensing codewords (passwords) from the IP of the server. Like OmniBack, and even many third party software products use the IP. Keep changing the IP and you'll be reloading license password/codewords every time you turn around.

To continue...let's say your an Oracle shop. How does your client resolve in it's tnsnames file. By server name (then the client must have the IP listed in either in it's hostfile or it references a DNS server); or maybe your tnsnames resolves to IP... Do you have MC/SG running on any of your servers...hmmm don't you have to have the IP for the pkg defined statically in your /etc/host file..

See the picture....look at your shop. Bet if you follow this logic that Patrick introduced you'll start realizing the whole can of worms this will cause.

Just my 2 cents,
Rita

[Rita C Workman]

Waiting for something to finish up, and I got to wondering....why is the network guy/gal so adamant about going DHCP? What is the problem with static on servers and certain network devices?

Is it that he/she is using only public IP's per chance? So maybe is running out of numbers?.....Could that be the issue? I would think that might be the only reason somebody would want to do something this lame....and then I would wonder if anybody had clued (like how I worked that in..) them in on using private numbers (like 10.x.x.x)for inside and then public number for outside.
Of course that would mean that your network person understands how to configure routers and firewalls properly to allow for translating these entries correctly.
Hmmmm...

But you didn't mention anything about your network...so I may just be rambling. Which is what I tend to do when I'm waiting on somebody else to finish up so I can start 'my work'.

Rgrds,
Rita

[A. Clay Stephenson]

By all means static; the last thing that I want is for a server's IP address to change. Moreover, if you are ever going to use ServiceGuard then the addresses of the packages/servers must be static. I would go one more level and insist that the dhcpd and dns servers be unix as well. Download the source from www.isc.org and compile. It is absolutely the best in the world; they developed it and maintain the standards.

The dhcpd from them is very powerful especially if you have users who might travel and attach over different subnets. ISC's dhcpd can even handle fixed ip addresses that vary according to the subnet - even with the same MAC address.

[Steven E. Protter]

static for servers.

There are many reasons, here are a few:

1) Server infrastructure needs to be doucmentted. You need to know what the IP address is, not guess.
2) You may want your server to work right even if DNS and DHCP servers aren't working properly.


SEP

[Pete Randall]

Frankly, Christine, I don't see any need for clients to use DHCP, either. We set up a pool of ip addresses way back when (far back enough that they were originally in /etc/hosts - all the windoze boxes that could potentially connect were pre-defined, with clever naming conventions so we could identify what floor and which section of the building they were on). When we tentatively poked our noses into the modern era and implemeted DNS, we still set up the pool of clients. When the Windoze "gurus" set up a new PC, they pick an IP address from the available pool and assign it. What does it take, an extra 15 seconds to scan and update the list? This ain't rocket science!

Pete

[Dave Unverhau_1]

I'm guessing that the network admin has torn his hair out oce too often over having to troubleshoot duplicate IP addresses on your network and is trying to fix the problem by getting a law passed, as it were, against static IPs. He's just trying to gain control of a situation that's making him feel helpless, probably. ...But such a solution is not the best choice in a unix server environment, as just about everybody else has pointed out.

DHCP makes all the sense in the world for PC's, especially if your PC-based workforce is mobile, moving their PCs from one subnet to another.

However, servers are by their nature fairly immobile devices. I've yet to see an Oracle server run on a laptop, although I'm sure some genius out there is doing it. (...just because it can be done doesn't mean it makes sense...)

It does make sense for a lot of reasons already given to set aside a range of static addresses for assignment to servers and create separate pools of IP addresses for DHCP usage, based on function, perhaps.

Good luck with your struggle!

Regards,

Dave

[Carl_35]

As everyone else (mostly) has said, servers static, clients (desktops, laptops) dynamic.

One thing that may affect your admin guy's way of thinking... there will be far fewer servers than clients. Adding the static ips to his daily life will not introduce much by way of complexity.

Let's say you have a network with 100 users. How many servers might there be? Email, database, www, and a few applications. Let's call it 10 servers. Not a big deal.

How many networks/routers is this going to involve? with 110 machines on the network, this COULD be done, if everything is housed in one location, on one subnet, two if using a DMZ to hide the internal network from the Internet.

Now up it by 10x. 1000 users, all using DHCP, so no problem there. How many servers? Still not very many. Probably much less than 50. Maybe some development/test servers have been added to the mix, a couple more applications, and a little redundancy.

A few routers now, but they likely won't change very much once they've been set up.

Also, security is enhanced by having the servers static. No one can bring up a laptop at the known ip address, router/firewall rules can be more granular, certificates are easier to handle, etc...

It seems to me this guy is daunted by the set-up of the network(s), but once properly handled, it is easy maintenance, and he won't even notice the static servers any more than he does the dynamic clients.

That's just my $0.02...

[Christine Hartman]

We do have 2 dedicated vlans for servers in the data center. Unfortunately one of the vlans is running out of ips..mostly due to the explosion of windows based servers in the data center. However, I do not see this as justification to force any server to Manual DHCP. I do understand that Manual DHCP "should" maintain the same ip, but because you have to register the mac address, problems will arise if you ever had to swap out a NIC. Once that NIC is swapped out, your ip will change until you manually go in and fix the dns entry. This is a strong argument for my case, but I wanted more examples to make it a stronger case and to rebutle any so called "reasons" the network group may throw out there to defend their case. In addition, I wanted to get a good sampling of what the majority out there uses and what is viewed as "best practices".

[Christine Hartman]

By the way Carl, we have about 150 Windows based servers and about 50 Unix based servers, we are implementing bind 9, we do have a DMZ, our firewall is still running gauntlet (not sure if this is changing). We support about 3000+ clients (desktops/pc/printers).

My guess is that someone is attempting to enforce this for personal or bias reasons..and is not really looking at the situation objectively and what is best for the business. Which is why it is important for me to stick with factual arguments. :)

[Stephanie Jenkins_1]

Static for Server

One of our customers we send CAD data to requires a static IP to connect back with our server to authiticate who the CAD data is coming from.

We went accross this bridge when changing from private to public IP's