Summary
Hosting on dynamic IP became a reality only after some service providers, such as DynDNS and NoIP, decided on a business model in which they earn advertising fees by giving away third-level domains and supporting those domains with their nameservers, and derive income from premium service, such as supporting top-level domains. It is with that service that we host uninterrupted servers on dynamic IPs. Before visiting a provider, you might want to check out DynDNS host record guide or NoIP host record guide.
The principle behind this is sort of on-demand DNS update. When an IP has changed, the DNS client simply updates the nameservers, specifically the A record. On receipt of a query, the primary nameserver will serve the IP stated in the A record. This usually takes place within 20 minutes. For comparison, a conventional nameserver will take up to 72 hours to propagate the new record.
Can I host a server on dynamic public IP?
Yes. The only requirement to make a host accessible from the internet is an IP. It does not matter whether it is dynamic or static.
Can I host a server without a domain name?
Yes. You only need a public IP to host a server. Domain name is just a convenient way of remembering Uniform Resource Locator (URL).
Why can't I host my webserver?
Your ISP has blocked port 80 on which the webserver is hosted. You can host it on a different port.
How do I find out whether my ISP has blocked a port?
Search for a utility such as Port Detective and use it to check the ports on the host in question.
Where can I sign up for free dynamic DNS service?
NoIP and DynDNS are two of such service providers. You can also search for others. Usually, you get a free third-level domain and dynamic DNS to translate that domain into your dynamic public IP.
How reliable is their service?
Those service providers use industrial-strength equipments to provide services to paying as well as non-paying customers, so it is not a question of how reliable they are, rather it is how reliable you are. And you are at best as reliable as your Internet Service Provider.
Athena restart on old public IP address even though the IP updater has successfully done the update. Why?
From SVN-7xxx, you can activate a configuration line in login_athena.conf to speed up this process.
Remove // to activate
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//ip_sync_interval: 10
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Or just add this line to login_conf.txt in import folder.
You may skip the rest of this section if you wish.
Here's a note on dynamic IP, using NoIP as example. Your host must have a valid public IP in order to get onto the net. In order for other people to find you, the whole world must know your IP. This propagation takes time. When your IP is changed by your ISP, you will have to tell the whole world again. Again it takes time. Since no one will inform the whole world of an ever-changing IP, NoIP makes a living by providing that service in the form of "your-ip = your-ro.no-ip.com". Now, when your IP changes, the updater tells NoIP the new one and NoIP undates its nameservers which in turn tell other nameservers in the world that "equation". That process can take up to 72 hours to complete (initiation) but typically less than 20 minutes. When your host reboots, the updater immediately get your new IP from the router and sends it to NoIP. But you probably set Athena to run as soon as Windows is ready. On powering up, Athena will send a request to the nearest nameserver for the IP of your-ro and sure enough, will get the old IP. Why? Because that is the most recent DNS record cached on nameservers around the world. That's on your part. The same process runs on the side of your members. A client will not connect if it couldn't get the IP of your-ro even though your-ro is on air. The work-around is obvious, but not easy. You can use applications like cron to schedule Athena to start only when the answer (your IP) from the nearest nameserver is the same that of your router.
Can I just edit my public IP settings to make it faster for Athena?
Yes, you can force Athena to start on the new IP by editing the configuration file. Remember to set it back to DNS though.
Will it be faster if I were to use IP?
Certainly. We are talking about a saving of as little as 50 miliseconds and typically less than half a second. The trade-off is that visitors to your server will be spending more (a lot more) time remembering and keying in your IP.
Can I host my own nameservers?
You can host your own nameservers if you have a top-level domain and register the nameservers (third level domains) along with their respective static IPs. The rule says each domain must be served by 2 nameservers, so you will need 2 static public IP addresses. Nameservers are sometimes hosted on private IP addresses to provide DNS service to a large network.
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