DYNdns

[wuchy143]

Hi All,

Does anyone know exactly what DYNdns is and how it's used? I'm unfamiliar with it and it seems like it could be a fun little tool. An example of how you would use it would be all I need. Reading wikipedia I just get confused.

 

[Sceadwian]

It's pretty simple. You have two choices, you can purchase a domain name yourself, or use one of their free domain name extensions, they point the name of your choice to their name servers and redirect it to your IP address, high speed Internet providers are technically dynamic IP addresses so yours can change at any time for any reason, so software installed on your computer, or even your router (I have a router that natively supports DynDNS) will contact the DynDNS servers and update the IP address any time it changes.

 

[Noggin]

Pretty much what Scaedwian said. I use no-ip for DynDNS here and at work. We actually don't need it at work because we now have a static IP address. No-ip can be used for free, as can many other services such as this. Port forwarding is also supported, so you can run a web server, FTP site, remote desktop, etc on your PC.

 

[KeepItSimpleStupid]

Everyone sorta neglected how it might be used. It allows you to run internet services hosted at home such as a web server. There could be cell phone app that needs to contact a server at home to turn on light or monitor an alarm system or even view a camera on your property.
Dyndns is needed to locate the network that device is on.

If you dont have a static IP address, then you must tell your router to "port forward" to a private IP and port number. You could have port 1000 forwarded to port 80 on 10.0.200.3. Port 80 is an http server by default. So if you went to myhome.dnsprovider.org:1000 you would be connect to an http server at home. Alternatively, you can get a fully qualified domain name like www.myhome.com

 

[Sceadwian]

Sorry KISS, no one neglected to mention that because it's simply not true. It's a convenience from having to track your machines current IP address manually and enter it if it changes, all such servers can be run on a home machine without DynDNS or an associated service.

Port forwarding has absolutely nothing to do with static/dynamic IP addresses, it is required to tell your router that anyone trying to access a specific port from the Internet will be forwarded to a specific machine on that network and has nothing to do with DynDNS or nameservers at all and is a completely separate subject.

 

[Reloadron]

DYNDNS is a business which can be found here. It is a tool and that is about it.

The tool works a little like this. When a computer connected to the Internet starts it obtails an IP (Internet Protocol) address. That address can be obtained through a router connected to a cable modem where the modem issues the address or it can be an IP address assigned through the cable modem. The ISP (Internet Service Provider) ultimately assigns the address. That IP address can be one of two flavors.

You can have a static or fixed IP address or you can have a dynamic IP address to for example a home residence. Either way this address is a collection of numbers. The big difference is a dynamic IP address changes while a static or fixed IP remains the same. Think of an IP address as no more than a location. Enter the DNS.

The DNS (Domain Name System) is just a way we resolve the numbers I mentioned for an IP address to a name. The analogy of a phone book is popular here. For example you can type into your browser's address bar either 204.2.118.143 or you can type in www.theblain.com and you end up at the same place. Both roads lead to the same place.

My ISP happens to be Road Runner and right now, today at this moment my IP address happens to be 76.190.145.237 so I could set up my own little web using that IP address. This would work fine right till my ISP dynamically changes my IP address. Just about all home users are assigned a dynamic IP which as mentioned changes on a regular basis. If I want I can setup my own static IP and pay for the service through my ISP. Barring that cost I can look to DYNDNS as a solution.

DYNDNS gives me some server space. They have a fixed IP. What they do is arrange to forward and receive data from your constantly changing IP address. That is all it is about. So if I want to set up anything web on my home system(s) it makes for a nice simple solution to my ever changing IP address. When my home IP changes it is sent to their servers.

This is useful for software like wordpress and similar software. Additionally it is useful if I want to set up a webcam and see what my dogs do all day when I am not at home (though I know they sleep).

Ron

 

[KeepItSimpleStupid]

Semantics.

The OP asked what it;s good for. I described what it's good for. To locate a machine on your network from the Internet. Yep, you l could run a mail server on your private network, but it would be nearly useless. FTP and http servers, could be useful on your own private network and it's not necessary to Dyndns. Using your cell phone to access an http server is totally related to Dyndns.

I went ONE STEP FURTHER and basically said you need to understand "port forwarding" in order to use Dydns.

I agree that "DYNDNS gives me some server space." this statement is a bit odd. What I meant to say was it gives your server a location on the Internet.

Sorry for the confusion.

 

[Sceadwian]

It's not semantics, the statement that DynDNS enables you to put servers on your home computer is simply not true, nor is port forwarding have anything to do with nameservers, and would only be an issue if the person was behind a router, which is again as I said a completely separate issue altogether and outside the scope of the original posters question.

I don't understand how you can call that going one step further, the original posters question was extremely simple and answered completely in the first reply, any inferred intent and continued additions outside of specifically what DynDNS is pretty pointless and leads to a lot of random additions to a thread like these posts we're making now =)

DynDNS nor any service like it does not give your server a location on the Internet,all it does is give it a name that can be attached to an IP address, static or dynamic, you can always use any server based on a home PC (that's not behind a router or firewalled) by simply providing the IP address of the machine, which although technically dynamic on most cable and DSL connections will not change very frequently.

 

[KeepItSimpleStupid]

Wikipedia defines (DynDns) as "It is best-known for its free DynDNS dynamic DNS service, which allows users to have a subdomain that points to a computer with regularly changing IP addresses, such as those served by many consumer-level Internet service providers."

While true, DynDns generally has to point to the public IP address of a router first and then the router re-directs the port to the computer and port handling the service. It does that by configuring port-forwarding within the router.

In a load balancing scenereo, dyndns could point directly to a computer. This is what I mean by things get really hard to define. In the "scope" of a "home network with a private IP" it would not. It points, INDIRECTLY, to a computer.

What makes the explanation wierd is: "Why would I want it to point to a computer with a varying IP address? Suppose I think "computer" is a computer on my private network and it uses DHCP, so "My computer" has a time varying IP address, right? For Dyndns to work effectively, you need a computer/service with a fixed IP on a private network attached to a router with a time varying public IP address.

Is that any better?

Uses for was not addressed in your post: https://www.electro-tech-online.com/threads/dyndns.121072/#post998007

The OP was confused with Wikipedia's explanation. I find Wikipedia's explanation confusing.

For the benefit of the OP, a public IP address is routeable. A private IP addess is usually 192.168.x.y, 10.x.x.x and one other obscure range of addresses. It is pointless to have dyndns point directly to 10.0.1.1. Again, what makes things confusing is that the router will respond to both a public and private IP address, say 10.0.1.1 within the approprite subnet and the public IP that will also point to the router.

Aside: At home I havn't the foggiest what goes on with my network because the modem is in bridge mode and the router does not have an http configuration page. It uses propreitary software. In order to access the modem configuration, I have to use 192.168.1.1 through a wired connection. I have not found a way to connect to the modem from within my network even if I changed it's IP address. It makes troubleshooting a real pain. I need to reduce the network to modem and single computer to troubleshoot and I have another modem configured that way.

I would actually like the OP to respond in his own words on what Dyndns really is.

 

[KeepItSimpleStupid]

"Dynamic DNS" is a better term to search for in Wikipedia: https://en.wikipedia.org/wiki/Dynamic_DNS

Dynamic DNS is a method/protocol/network service that provides the capability for a networked device, such as a router or computer system using the Internet Protocol Suite, to notify a Domain Name System (DNS) name server to change, in real time, the active DNS configuration of its configured hostnames, addresses or other information.

This definition, I don't have a problem with. The explanation that follows is sufficient.

 

[wuchy143]

It's pretty simple. You have two choices, you can purchase a domain name yourself, or use one of their free domain name extensions, they point the name of your choice to their name servers and redirect it to your IP address, high speed Internet providers are technically dynamic IP addresses so yours can change at any time for any reason, so software installed on your computer, or even your router (I have a router that natively supports DynDNS) will contact the DynDNS servers and update the IP address any time it changes.

I understand what Sceadwian is saying here but I don't see the big picture. Why use DYNdns? What do people use it for?

 

[Noggin]

You use it so that you can access a computer over the internet without having to know the IP address of it. For instance, I have a spreadsheet containing the food I eat on my computer. When I'm at work and I need to update it, I run a remote desktop application using my DYNdns assigned name to get to my PC so that I don't have to remember the IP address.

At work, we used to use it (now we have a static IP address) so that we can run services on our server. We just released a product that periodically connects to our server to see if there is a new firmware available. If there is, then it requests to be bootloaded. We couldn't do that without either a static IP address or a domain name. The product would go to blah.no-ip.biz, which was basically forwarded to whatever our IP address happened to be at the time.

 

[wuchy143]

Got it thanks!

 

[Nigel Goodwin]

I understand what Sceadwian is saying here but I don't see the big picture. Why use DYNdns? What do people use it for?

A popular use is web cams etc, you can access it from anywhere in the world, and DynDNS gives you a fixed address for your variable IP address.

 

[Sceadwian]

Actually, it gives you a fixed name not an address as I've said several times now, but lets not get technical here, oh wait.. this is a technical matter! =) Keep in mind Dynamic DNS services can have problems with some providers because of caching of dynamic IP addresses. The moment the IP address changes there could be minutes or hours until it works it's way through DNS caches, this isn't a problem if your IP doesn't change often, or if your ISP doesn't use long term DNS caches.

While DNS transactions are small their aggregate bandwidth with a large number of users can add up, which is why cache servers are used.