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bytebrowser 06-14-2003 02:35 AM

Static IP Address

Although I am studying an IT degree, I am still pretty new to all of this.

My question is in regard to static IP addresses. How do I get a static IP address so that i can run a full time web server? IS this something I need to get from my ISP or is it something I have to apply to another organisation for?

Thank you,

evslin 06-14-2003 02:37 AM

Talk to your ISP. If you're on cable/DSL chances are you've been assigned one, but they'll probably yell at you for running servers ... but what they don't know can't hurt them right? ;)

bytebrowser 06-14-2003 02:48 AM

I am on ADSL, and I think i get a new one assigned to me each time I reconnect. So I will give my ISP a call now.


hornet 06-14-2003 04:09 AM

Most Australian ADSL providers dont issue static IP's. Some will assign you one if you ask, and charge you $20 a month or so for it. Others only allow it on their business plans.

I use TPG how ever, with unlimited downloads and a static IP standard, as well as allowing servers, its good value at $70/mo for 256k and $80/mo for 512k

Other than that you can buy a domain, then signup with who can have that domain pointed to your dynamic IP, with in about 5 seconds of updating thier database with the new IP, via a client program running on your computer.

bytebrowser 06-14-2003 07:49 AM

the dyndns is quite cheap for what it does. Has this a stable reputation?

hornet 06-14-2003 08:18 AM

I have use it with one of the subdomains they provide free. And it was very stable and reliable. I have a static IP now, so its not much of a concern with me.

One of my instructors uses with with his Telstra ADSL connection and speaks very highly of it.

bytebrowser 06-14-2003 06:50 PM

I might try that then. I am with Telstra and they want to charge me ADSL Subscription + $20 per month + 20c per Mb Dowload from what I can read.

This may be a stupid question, but when I have 2 computers on the same router, does each computer have a seperate IP address or do they share the same when on the net?

hornet 06-14-2003 10:50 PM

Your router will be assigned the IP address. your computers will most probably have internal ip addresses, such as 192.168.0.*

bytebrowser 06-14-2003 10:55 PM

yeah that's right, but what i don't understand is that the external IP address will point at the router, but from there how do things happen? ie. how will the outside world know to go to the linux box directly. is there some concatinated IP address like or how does it work?

hornet 06-14-2003 11:07 PM

its a setup called NAT (Network Adress Translation) i think in the packets that it sends, it encapsulates the internal IP, so when the packets are sent back, it knows what internal IP to forward the data on to. try doing a google search for NAT or Network Adress Translation.

You will need to setup port forwarding on your router though. You want the router for forward all requests made on port 80 to go to ur linux box. port 80 is the standard http port.

baldy3105 06-16-2003 05:13 AM

Network Address Translation quite literaly means what it says.

192.168.*.* networks do not exist on the internet. This means yo can use them internally without clashing with a real internet site.

The downside of this is that if you send a packet to an internet host with a source address of, which will get there as the internet does not check source addresses of packets, the host will have no way of responding to you as the network you appear to be comming from doesn't exist.

So we have to use NAT to pretend that you are comming from a real network.

When an inside (your lan) host sends packets to an outside (the internet) host the source address of the packets is edited so that what used to read now reads

Outside hosts can now respond to the globally unique address and because the NAT box (your router) builds a translation table to keep track of outgoing sessions it can translate the destination address of the packets comming back.

So NAT does the job, however Incomming connections now have a problem.

No one can HTTP to your inside address as it doesn't exist from the internets point of view. Of course they can connect to your real global address, but because your router doesn't have a port 80 listener, anyone trying to HTTP to your global address won't succeed. Unless you tell your router to forward requests for this port to somewhere else (i.e your inside web server). Once you tell the router where port 80 connect requests are sent, it will NAT and forward the request to the inside host.

(some routers have management access via port 80 which you may need to turn off as it may override any port forwarding you configure).

bytebrowser 06-16-2003 05:26 AM

ok Pete,

I fully understand what you have explained to me. Is there some name for this section in my router.

The sections I have in the config are:
Inital Setup
System Setup
Save All

Under which of these sections would I config the 80 port?

I can give you my IP address if it helps

bytebrowser 06-16-2003 05:30 AM

Also the router is an Alcatel Speed Touch Pro

baldy3105 06-16-2003 06:06 AM

Check this out -

It has a section on nat and how to configure it. You can do it all from a browser page by the looks of it. The way I read it, you need to enable nat on the PPPoE interface, then add a nat entry which takes care of the dynamic address problem.

Also if you only have one externally accessible server then simply add a default server entry to your server.

If it were a cisco I could be more specific. :)

bytebrowser 06-16-2003 06:36 AM

Well i am not a cisco! :)

That site did help. I also found my manual which i thought i had lost. I think this is the area that i need to make my changes. Have a look at

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