IP Addressing

[rumrugby]

hi everyone,

i was just wondering, how do places like RackShack (EV1), when they have just say like 1 internet connection to serve like 1000 servers....how do they split that connection up so that each one of those servers has a external IP address without using DMZ of any internal ip addresses???? what hardware do they use?


thanks :)

[existenz]

No major ISP has just *ONE* internet connection. For most of them it technically is one pipe bonding many different circuits from many carriers together. Though big customers will most likely have their own choice seperate connections dropped just for them not part of the ISP's network.

Let make it simple they have a single OC192. They have a entire datacenter and they want to support right now 1000 servers. They will request 4 class C block which will give them 254 usable public ip address. Then it is as simple as entering that information in their router and all the address work.

This is wicked over simplified and it does not work exactly like this but it helps you get the idea. DMZ is more of a SOHO deal. It is used to give a machine with a private ip address the ability to be see from the public internet.

As for hardware it all depends on what they are doing, but it is a safe bet that most of the routing equipment is Cisco and sometimes for most ISP's you will see Cisco, 3Com, Nortel stuff like that. Their is also a host of load balancing and bonding equipment by a variety of manufactures.

[rumrugby]

so is it therefore possible to have a aDSL connection or sDSL for that matter and have it shared between several servers however the external IP addresses are sitting on the servers rather than the router???

[ToyMaster]

Yes... it is possible to have an xDSL line with multiple IP addresses... Heck, I can provision one for you that could give you a full Class C (256 addresses) routeable IP block... But your xDSL provider needs to be able to support it, your xDSL router/bridge needs to be able to use it, and more importantly you will need to PAY for it... You can't just get a NetGear/Linksys Cable/xDSL router for a standard cable/xDSL line and hope to be able to setup mupltiple DMZ's... :D

While you could theoretically setup port forwarding to host multiple servers on a single ip, but that wouldn't be a very professional setup for a web host.. :eek:

-Robert E. Plummer
President, PP&F NetWorks, LLC

P.S. I can provision a full T-1 circuit for about $500.00 for most locations, with verying IP options. Contact me for more info. ;)

[existenz]

It does not work like that at all. IP address are handed down in a chain of succession. In a DSL connection this ISP will assign the bridge a series of ip address. These can be public ip address from a DHCP pool like on some of the PPPoE aDSL loops. These can be static ip address like those found on sDSL loops.

It does not matter the ip address are assigned to the router one level up from your bridge. You then have the ability to assign those to your server.

Actually rereading what you said I think you basically get the idea but not exactly. You seem to be thinking about how many home network are setup with one public ip address a few computers behind like a linksys router. You have a pool of private ip address from that linksys router and then the ability to foward a port from the public ip address to one of the private ones on your internal network.

If you are looking to have a server one your DSL connection all you will need is a static ip address (or two).

[nobaloney]

I run two networks in my office, off one ADSL line suppled by my local telco, SBC.

I buy 5 static IP#s from them. There was a one-time charge of us$150, and a monthly charge of us$15 for those 5 IP#s. I have a switch between my DSL modem and my router. I feed four of the IP#s from that switch to my "test server farm" of four servers. These servers are "on the Internet" exactly as if they were at one of our data centers; they each have a static IP# and can be addressed as any other server on the Internet. That's my external network.

The fifth IP# is wired from that switch to my DSL router. My DSL router (I use an SMC Barricade) serves my internal network, using non-routable IP#s. The router also acts as a firewall for my Internal network, and supports a parallel-port printer, letting it act as a network printer on my internal network. I also plug my VoIP telephone system into the internal network.

The key, if you're going to serve sites from a DSL line, is that you must get multiple static IP#s from your ISP, one for each of your servers, and if you also want a router for an Internal network, VoIP telephony, etc., one extra static IP# for that.

I hope this helps.

Jeff