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zrob_12
join:2009-01-17 | DHCP vs Static IP
What are the advantages / disadvantages to using DHCP to serve addressses to customers? Likewise, what are advantages / disadvantages to giving all customers internal static IPs? Any real life experiences with each? | |
ponline
join:2004-03-04
presheva
| DHCP advantages: you can change your costumers ip without a truck roll, everything automatic, no need to touch clients computers just plug the cable.
Disadvantages- none.
Note: except it may have some problems with laggy wireless network, but then again you will have a lot of problems with that kind of network. Also, mac bride thing may cause some problems on wireless bridges, but even with a wireless bridge in all the cases that i had it worked no problem.
Manually entered static IPs; Advantages - none (except in bad designed wireless network)
Disadvantages: A lot
To mention a few:
Manually entering clients ip addresses, in case they mess them up or reinstall lan driver or windows, you need a truck roll to enter the ip addresses.
In case you change your ip scheme, imagine going to every client to change their ip address! | |
TomS_
debugger it
Premium,MVM
join:2002-07-19
Australia
1 edit | said by ponline  :Disadvantages- none. Disadvantages: at least one.
You never really know which customer is on which IP address. Inifinite leases help, until you reload the device handing out the IPs (unless it maintains its state in some sort of database.)  | |
gunther_01
Premium
join:2004-03-29
Saybrook, IL
| reply to zrob_12
I have a different view point, but also have a different wireless network layout then ponline.
We use our wireless radios as NAT routers and assign all of those radios static IP's. We then use the radio to hand out a private IP to all wired devices connected to it. We don't bridge anywhere on our network.
DHCP for us flaked out here and there causing customer calls and complaints. The illustrious "page cannot be displayed" error LOL. And that was with equipment we owned and operated ie. DHCP to the CPE's. So here are my pro's/Con's
DHCP pro
Easy
automatic
quick subnet / block changes as needed
DHCP Con's
You will still need to pair your MAC to IP's to a particular device, or you loose the ability to "know" who has what IP (Calea, to name one problem with that)
Random no IP on device or computer problems, which make phone calls and or truck rolls inevitable (Truck rolls due to unknowledgable customers that you can't walk through repair commands and the like)
You will probably bridge the CPE to the customer in most cases. If your radio does not bridge properly DHCP doesn't work very well. Same issue with AP's and your overall network layout since DHCP doesn't "route" You will need DHCP relay that actually works to have one central pool, or do DHCP at each site/ AP
Static Pro's
It NEVER fails in our case, but may with statics on PC's
IP's don't change so we can monitor clients with ease, and login to client radios quickly with IP already in the customer file
Static Con's
You have to enter in the IP while on site, or at least enter it in in the first place (Whaa  )
Not "easily" changed for major network reconfigurations.
It's not the norm, so no one likes it haha
And before someone asks, if a customer needs a public, we route them one from the pool. | |
TomS_
debugger it
Premium,MVM
join:2002-07-19
Australia
| I suppose thats why I prefer PPPoE so much.
Authenticating your users via RADIUS means that the PPPoE server can send the IP assigned to that customer in the start packet for their session. So you'll always know which user is associated with which IP.
And the PPPoE server can be configured to periodically send accounting updates to the RADIUS server to keep track of how much data they are uploading/downloading for billing purposes.
AND if you are clever enough, RADIUS can also issue CoA (Change of Authorisation) packets to the PPPoE server to dynamically adjust session parameters, such as a rate-limit to be applied to their session once they exceed their quota, etc.
And theres plenty more. RADIUS and PPPoE: a lethal combination. | |
gunther_01
Premium
join:2004-03-29
Saybrook, IL
| reply to zrob_12
Can't complain about PPPoE, I know . But, it does have some of the same drawbacks as DHCP, and can be dependant of your AP's capabilities for "advanced" features.
I would probably still use it if I hadn't had the problems we did back in the day. I got spooked and it would be a PITA to do it now. But you never know I get closer all the time to trying it again. | |
ponline
join:2004-03-04
presheva
| reply to gunther_01
said by gunther_01 :I have a different view point, but also have a different wireless network layout then ponline. I don't use DHCP on my network either, it was only my opinion about DHCP vs static.
In my WISP use radius + pppoe to authenticate CPE's.
The ony DHCP is from the CPE's to the wired client devices.
Still a would prefere DHCP against static anytime. most of the AP/routers now can do DHCP server, especially if you deal with advanced routers like mikrotik.
As for discovering which ip belongs to which client you can keep a database with mac adress of the CPE's which is same as kepping a database with client names with ip adresses (in case of static).
But IMO i woudnt sugest anyone to do DHCP on a growing network unless he uses an advanced AP with access lists of MAC adresses updated from a radius (or WPA-radius).
Imagine if you grow past 300 clients what a PITA would be finding out which IP(in case of static) or MAC (in case of DHCP)belongs to which client.
For a growing ISP ofcourse I suggest pppoe auth. (and you have all the other goodies that TomS in a combination with Radius it makes your life much easier. | |
gunther_01
Premium
join:2004-03-29
Saybrook, IL
| reply to zrob_12
ponline,
We/you could keep a database of MAC's to customer, but that doesn't tell you the IP right off in a DHCP environment. You would either need to "static" map your DHCP server IP's to MAC addresses, or parse some kind of DHCP log to find your IPs and when it was used (since they would change fairly regularly). That's what I was getting at there. I can look up a customer and the IP is right there every time.
I could and can do DHCP with ISC built in to my Star AP's. I could and can do PPPoE as that's built in also. I choose not to because I never have to worry about radius crashes, DHCP failures on either side of a link, PPPoE glitches, MAC to IP static assignments (which is about the same as static IP's to me)
Believe me I know how much a PITA it is when you get a new IP block and have statics. That happened to me when we had to upgrade carriers. 100+ customers I had to re-do So yes, that does suck. My customer support line is attached to my hip via cell phone. It doesn't ring, and I like that. That's about all I can say really. But in reality, when done right, all of them (DHCP, PPPoE, Static) work very well. | |
raytaylor
join:2009-07-28
| reply to zrob_12
My internal network is unrouted - at the moment while it is still small.
I use DHCP to issue ip addresses in one subnet which takes people to a hotspot ticket page, and static ip addresses for fixed wireless users who have a residential subscription which takes them to another gateway. Also the cpe radios for these static ip users are nat routers as well so the users in their homes have their own ip addresses in the 10.1.1.x range which are issued by their CPE radio. | |
ponline
join:2004-03-04
presheva
| reply to gunther_01
said by gunther_01 :I could and can do DHCP with ISC built in to my Star AP's. I could and can do PPPoE as that's built in also. I choose not to because I never have to worry about radius crashes, DHCP failures on either side of a link, PPPoE glitches, MAC to IP static assignments (which is about the same as static IP's to me) gunther, how many clients do you have?
I used to deal with static ip addresses in the beginning of my wisp, that time most of CPEs had no router mode and no pppoe built in, they worked as bridges.
I used to give manually entered statics to bridges, and DHCP to wired client computers behind the bridge.
IP addresses of client computers behind a bridge were handed from a DHCP server in every AP.
The main idea was not to enter ip addresses manually on client computers, to avoid the support for that.
In mikrotik you can make a static lease with one click, so as soon as they got their first ip we made it static, and the same ip was assigned to same client every time.
So we kept a list of clients and CPE bridges ip addresses manually.
No technical problems at all.
If a costumer calls , you need to search his name to find out his IP, and then find out in which AP is connected then ping it or check his signal. It is not a big deal, but depends on the number of costumers. The more clients you add the more difficult would be to keep track on them manually. I don't think that is efficient method with 100-200+ clients.
Plus the billing problem, there should be someone who disables and enables those clients when they payement deadline passes.
So after we passed 100+ clients we started to have needs for a better ip management scheme, and billing method.
And I had to do a lot of research and testing , and reading (in this forum too) and ended up with pppoe and radius.
Now a client calls, we search his name in radius, his ip comes out and the NAS he is connected. His paement deadline, the radius sends e-mail automatically before disabling his acount, a lot of other goodies, billing history, traffic, log on/off statistics, we set bandwidth limits, bursts, caps from the radius, etc etc.
Another good thing, our installers have to enter only an username and password on the cpe and find one of our APs in range, no ip adresses.
We have two full time field installers, each can do up to 4 installs in a day in a good weather.
Now we have 1000+ active clients,we support them with two full time support employees each in one shift, who do network monitoring , selling, and phone support in the same time, and when is the need for field intervention they combine with installers.
But most of the days we drink cafe and make jokes, watching our PRTG server (similar to mrtg) and the dude (mikrotik monitoring software) shining in green color.
Depending on the wireless OS (firmwares) in use, they may give you pppoe glitches (I've only heard) but i never experienced a pppoe problem with mikrotik in my 5 years of using it.
Every Radius has his tweaking and understanding problems it all depends from the experience and maker but once you set it, you may forget it. (god i don't know if I'm able to install my radius server again, it was long time ago .
But radius is the essential server for the ISP business , sooner or later every decent sized ISP will have a need for one.
I don't think it would be that easy for me if it was not the pppoe and radius.
Pardon me if a part of this post is OT. | |
gunther_01
Premium
join:2004-03-29
Saybrook, IL
| I will try to answer all of that
We, or I should say I, have 6 towns, 2 repeaters, and about 150 customers and growing all the time. This is done by myself and one part time installer/tech, another part time phone call taker, and a part time half of the billing side person. I do all the support calls, network design,back end stuff,inbound money data entry, deposits, overall billing, and dictate what the others should be doing lol... All that and a full time job, 3 kids, and a wonderful person draging me through legal matters all this year haha. I'm a busy man.
Network wise what I ran into years ago with PPPoE was the bridge clients didnt want to work consistantly. And clients dropped out a fair amount of the time. I am sure you know what a headache that was, so I went with static on CPE's, and handed out client IP's with DHCP. Even that goofs up with customer routers every now and then, so we static routers now as well.
As i look foward to current trends in billing and bandwidth controls I am leaning towards PPPoE as well. Since I read just about all the forums and am the only one that makes large changes to the system, I too keep myself pretty well informed. I could probably do some amazing things in my area given enough time to implement them for our customers, but time is NOT on my side either from my own life or technology as a whole Lol.
For us Star doesnt have a one click function for DHCP statics, so that is a bit time consuming. So i dont do that and chose to just set it once at the CPE. The IP is put down on the billing reciept and its added to the customer information in the computer. Our IP scheme is specific to each town/antenna so its very easy to find someone if just by IP or reverse name to IP Lookup. We also use PRTG and Cacti for graphs and customer status's. Mainly PRTG for AP's, BH, and higher dollar customer stats. Then Cacti for everyone else.
I in NO way am dismissing PPPoE and radius. Since I know what it can do. But for our smaller size, lack of good techs, time, and current set-up it's tought to implement at this point. Almost not worth it. With that said, you are correct in that the larger you get it becomes an almost mandatory function. If for nothing else to have better, and easily automated tasks for customer management. I am constantly looking for "better" ways of doing things, and that is why I say it looks better all the time | |
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