Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

How can a computer with dynamic IP work as a WebServer?

share|improve this question
up vote 25 down vote accepted

I have done this before and the process is pretty straightforward.

I ran a webserver on a dial up account that needed to disconnect and cycle IPs every 12 hours to be in compliance with my ISP Terms Of Service at the time. I will assume in your case you do not need to worry about the logic to keep the thing dialed up, so I will skip right to the next part.

the first thing you need to do is create a resolvable Fuly Qualified Domain Name that is resolvable on the internet. You can do this if you run your own DNS server or you can use a free service like DynDNS to create a static, but resolvable name you will use to get to your webserver.

Once you have selected your domain name and have a valid DNS entry to resolve it then next step is to install the DynDNS update service on your webserver which will update your DNS entry dynamically when your IP changes.

The next step is to build your webserver. I have used both IIS and Apache succesfully in this scenario. Whichever server you use is a matter of personal preference.

After all that is complete, you will need to make sure that your router/firewall is configured to port forward to your webserver inside your network. I recommend forwarding port 80 which will make the site accessible to everyone who types the FQDN into their browser. If you want to keep this server private, you might consider putting the webserver on another port.

enter image description here

DynDNS Services Page

share|improve this answer
Hard to make more complete than that. – Gnoupi Aug 10 '09 at 13:00
I tried to use from my Linksys WRT54G router, and dyndns claimed I was updating too frequently and kicked me off. Linksys was not interested in fixing this bug. So you may have to run the update program from dyndns on your PC, not the one built in to your router. – bobmcn Aug 10 '09 at 13:41
I would always recommend using the PC DynDNS update service for this very reason. – Axxmasterr Aug 10 '09 at 15:17
You could do it without port 80, without requiring any extra work from the user, by making the your DynDns host on your account connect to your updated dynamic IP at the specific port, right? – Mk12 Oct 15 '09 at 21:15
DNS does not support port forwarding. A DNS server performs the sole function of matching DNS records to IP addresses only. No port information is exchanged between the DNS server and the client regarding the appropriate port to connect to. That is more a function of the app making the connection. It intrinsically knows which port to use depending on which service it is connecting to. If your ISP is blocking port 80 on their egress filter, then you will need to use a port that is not blocked. Most people use 8080 for that, but really any open port will do the trick. – Axxmasterr Oct 16 '09 at 13:14

I think you are looking for a dynamic DNS service. There are several ones, here is one example : No-IP

You will have to create an account, then have a software running on your computer which will update your IP on their server.

After, there will be an address like,, etc. which will point to your computer.

Other possibility, if you want to host a small casual site and you want rather something simple to configure, you could use Opera Unite. Directly from Opera, it allows you to host a webserver (or directly a file/photo server), and takes care about the dynamic DNS itself.

Keep in mind though that this is a solution for a rather "volatile" and personal website, which you would like to show to friends, without especially having it online all the time.

The "Unite" service of Opera is still in beta at the moment (though already stable).

share|improve this answer
I tried Unite (follow the link in my answer to another answer beyond that). Its not very stable. I'd still suggest sticking to DynDNS if you intend to leave the web-server un-attended (for now). – nik Aug 10 '09 at 12:51
When I was using it, it was quite stable. Do you have some reviews or articles about it ? I'm curious. – Gnoupi Aug 10 '09 at 12:59

Are you looking for DynDNS?
Check Getting my IP address?

share|improve this answer

It works by having a little helper program running on your computer that updates the DNS entry whenever the IP address changes.

share|improve this answer

As mentioned else where, DynDNS service will update a name server (where gets translated to or whatever) periodically.

I just wanted to add that some network routers have this feature built in, like most Linksys routers. That way you don't even need software running on the computer.

share|improve this answer

I use for the same purpose as DynDNS and it doesn't cost me anything, and it has a updater scrip that I run on my linux server. I use StartSSL to generate a valid certificate also.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .