Dynamic IP Drama..

Forums › Spark New Zealand (including Skinny and BigPipe) › Dynamic IP Drama..

owenw

27 posts

Geek

#35973 17-Jun-2009 21:14

Hi there,

I've decided (and set-up) a server at home and am going to be dabbling in doing a bit of hosting and having remote access to my network at home.

So I've got a server setup and running Windows Server 2008, and IIS and everything - this accessible from the current IP on the outside world (using a seperate connection to test this), and I can verify that it is accessible. The ports are all forwarded, yaddah yah...

Now, I've only got a dyamic IP address, and I don't have an option of changing this - I wish I could go static but do not have a choice.

I've messed around with this heaps previously, and have yet again, set up an account with dyndns.org so that I can access the server all the time from a single address. This being owenw.doesntexist.org - my problem is, that even though this is being updated (as reported by the DYNDNS client on the server) and the fact that I can definately view the server via the current IP on the outside world, the address will not work, even though it responds to pings.

So my question is, what is going on here? Why can I not access it when using the auto-updated dydns domain, but can when I use the IP?

Any help is much, much appreciated, and I hope I've been detailed enough :)

nitrotech

1285 posts

Uber Geek

#225998 17-Jun-2009 22:22

Have you done a tracert owenw.doesntexist.org to see where it's timing out, also when you ping it i'm guessing that it's pinging the correct address?

I run my connection through dnsexit and it's fine, some ISP's cache the DNS results so sometimes when there is an IP change it can take some time (many hours) to update.

kdn

203 posts

Master Geek

#226242 18-Jun-2009 12:17

what plan are you on that doesn't give you a choice of static IP? unless your on the go-large you can get it on any plan? its $20 a month unless your on a pro plan in which case its free. xtra.co.nz/staticip

either way, nitrotech is right, the way DNS works is there are top tier servers and 2nd teir, 3rd teir blah blah and when a change is made it can take upto 12 hours to propagate right through everyone.

One option is to use a different DNS server, ie, if you use opendns.org as the dns server on your PC at the remote location then you may find your dynamic dns works a lot better and is updated faster. But of course that will fix your issue but other people accessing your site may not be so lucky which is why you have to be careful with dyndns if its a public site.

http://freedns.afraid.org/ is one I have used and worked.

Flamer.

Ragnor

8218 posts

Uber Geek

Trusted

#226469 18-Jun-2009 22:22

Have you added the host address owenw.doesntexist.org to the host header setting for the website in IIS? If not try that.

mjb

996 posts

Ultimate Geek

Trusted

#226487 18-Jun-2009 22:59

kdn: >either way, nitrotech is right, the way DNS works is there are top tier servers and 2nd teir, 3rd teir blah blah and when a change is made it can take upto 12 hours to propagate right through everyone.

Almost. DNS propagation delays are purely related to any given DNS record's TTL, or Time-To-Live. The majority of records in the wild have a TTL of 12 or 24 hours, but it's not uncommon to see up to a week, or as short as 5 minutes.

What happens, is that an initial query by a user causes their DNS server to look up the domain asked for. This starts off by asking the root servers (top tier as you put it) where the TLD is (.com, .org, .nz, etc). These TLD (Top Level Domains) have their own DNS servers, which are then asked where the next domain is (.co.nz). The next query is to the .co.nz servers to ask where geekzone.co.nz is. The next query is to ask the geekzone.co.nz servers where www.geekzone.co.nz is.

This record has a TTL, and what it indicates to the querying server is that it should cache that result for that many seconds, and not bother re-querying until that time has expired. Once it has, the entire query is started over - with exception of any records used to find the ultimate result that haven't themselves expired. (for example, .co.nz may have a TTL of 48 hours, but geekzone.co.nz only has 2 hours - this means the roots and .nz will not be queried for 48 hours, but .co.nz will be queried for geekzone.co.nz every 2 hours. Assuming that the querying DNS server is serving a geekzone user with ADD that refreshes the forums_unread.asp page every 2-3 minutes :) )

The above is a pretty general explanation, there's more to it than that. I've not touched on Negative TTL's which are even more confusing.

The last point to mention is that most dyndns servers apply a TTL of 1-5 minutes on their dyndns records.

Here's an example query tree:

$ dig +trace www.geekzone.co.nz

; > DiG 9.5.1-P1 > +trace www.geekzone.co.nz
;; global options: printcmd
. 41366 IN NS D.ROOT-SERVERS.NET.
. 41366 IN NS I.ROOT-SERVERS.NET.
. 41366 IN NS G.ROOT-SERVERS.NET.
. 41366 IN NS K.ROOT-SERVERS.NET.
. 41366 IN NS L.ROOT-SERVERS.NET.
. 41366 IN NS F.ROOT-SERVERS.NET.
. 41366 IN NS H.ROOT-SERVERS.NET.
. 41366 IN NS E.ROOT-SERVERS.NET.
. 41366 IN NS B.ROOT-SERVERS.NET.
. 41366 IN NS A.ROOT-SERVERS.NET.
. 41366 IN NS M.ROOT-SERVERS.NET.
. 41366 IN NS C.ROOT-SERVERS.NET.
. 41366 IN NS J.ROOT-SERVERS.NET.
;; Received 512 bytes from 127.0.0.1#53(127.0.0.1) in 17 ms

nz. 172800 IN NS NS3.DNS.NET.nz.
nz. 172800 IN NS NS7.DNS.NET.nz.
nz. 172800 IN NS NS1.DNS.NET.nz.
nz. 172800 IN NS NS4.DNS.NET.nz.
nz. 172800 IN NS NS6.DNS.NET.nz.
nz. 172800 IN NS NS2.DNS.NET.nz.
nz. 172800 IN NS NS5.DNS.NET.nz.
;; Received 394 bytes from 198.41.0.4#53(A.ROOT-SERVERS.NET) in 12 ms

geekzone.co.nz. 86400 IN NS ns2.iconz.co.nz.
geekzone.co.nz. 86400 IN NS ns1.iconz.co.nz.
;; Received 110 bytes from 202.46.189.130#53(NS4.DNS.NET.nz) in 160 ms

www.geekzone.co.nz. 3600 IN CNAME geekzone.co.nz.
geekzone.co.nz. 3600 IN A 210.48.73.74
geekzone.co.nz. 3600 IN NS ns2.iconz.co.nz.
geekzone.co.nz. 3600 IN NS ns1.iconz.co.nz.
;; Received 140 bytes from 210.48.66.1#53(ns2.iconz.co.nz) in 155 ms

(in this instance, .nz servers answered where geekzone.co.nz is, rather than where .co.nz is - this is because .nz DNS server have every .nz domain, the .nz subdomains are not separated out onto separate servers like some other TLDs)

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mjb

996 posts

Ultimate Geek

Trusted

#226488 18-Jun-2009 23:02

Oh, I should mention that the TTL's are visible above - the number after the DNS record. www.geekzone.co.nz is currently set with a TTL of 1 hour (3600 seconds), whereas the records that specify where the GZ DNS servers are have a TTL of 1 day (86400 seconds).

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