Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




47 posts

Geek


# 74750 6-Jan-2011 18:23
Send private message

I'm having a problem awfully like what's described here: http://www.geekzone.co.nz/forums.asp?forumid=39&topicid=66599

Same error message, local hosts entries, and I can ping but not access via browser

I developed a website, then upload it to my US based testing server, created DNS entry for it to point to that server. Because I need to check it right away, I don't want to wait for the 48 hours or so until the new DNS fully populated. So I add it to my etc/hosts file so I can access the website on the test server in US straight away.

The error is:

Network Error (dns_unresolved_hostname)

Your requested host "xyz" could not be resolved by DNS.
For assistance, contact your network support team. 


I spent all day trying to figure out what's happening, but I really have to calm myself down after making a call to Telecom 'technical' support.

Telecom 'technical' support kept thinking I'm a web developer who is trying to get web development support from Telecom. And because I can access all other websites, the attitude I'm getting is that this isn't Telecom's issue.

Can anyone please tell me how I can work around this issue?



View this topic in a long page with up to 500 replies per page Create new topic
 1 | 2 | 3
1476 posts

Uber Geek

Subscriber

  # 424739 6-Jan-2011 18:30
Send private message

asianbro: I'm having a problem awfully like what's described here: http://www.geekzone.co.nz/forums.asp?forumid=39&topicid=66599

Same error message, local hosts entries, and I can ping but not access via browser

I developed a website, then upload it to my US based testing server, created DNS entry for it to point to that server. Because I need to check it right away, I don't want to wait for the 48 hours or so until the new DNS fully populated. So I add it to my etc/hosts file so I can access the website on the test server in US straight away.

The error is:

Network Error (dns_unresolved_hostname)

Your requested host "xyz" could not be resolved by DNS.
For assistance, contact your network support team. 


I spent all day trying to figure out what's happening, but I really have to calm myself down after making a call to Telecom 'technical' support.

Telecom 'technical' support kept thinking I'm a web developer who is trying to get web development support from Telecom. And because I can access all other websites, the attitude I'm getting is that this isn't Telecom's issue.

Can anyone please tell me how I can work around this issue?


What is the website? I'll see if I can access it from where I am on TelstraClear.




Laptop: MacBook Pro (15-inch, 2017)
Desktop: iMac (27-inch, 2017)
Smartphone: 
Additional devices: Unifi Security Gateway, Unifi Switch, Unifi AP AC HD, Unifi Cloud Key
Services: YouTube Premium, Wordpress, Skinny Mobile and Broadband, G Suite

 


BDFL - Memuneh
64980 posts

Uber Geek

Administrator
Trusted
Geekzone
Lifetime subscriber

  # 424752 6-Jan-2011 19:00
Send private message

Accessing from other ISPs is not a problem. The problem is that having the entry in the hosts file make your PC resolve the address, but when the request goes out the proxy can't see it so you get this error.

You could make the domain a default in your server and browse by IP instead. Still would have problems with any resources where the full URL is used though.

Or try http://www.cloudshare.com and get free account to create a virtual machine and test from there instead.




 
 
 
 




47 posts

Geek


  # 424754 6-Jan-2011 19:06
Send private message

I have removed my local entries but still the same error. I guess without local entries I just have to wait until the DNS is populated?

710 posts

Ultimate Geek

Trusted

  # 424756 6-Jan-2011 19:15
Send private message

Have you considered using a dns entry with a deliberately low ttl - say 60 seconds - at least while testing ?




No signature to see here, move along...



47 posts

Geek


  # 424758 6-Jan-2011 19:22
Send private message

Hi BlakJak,

How would that make a difference? Wouldn't it still take around 24-48 hours for a new DNS to populate?




47 posts

Geek


  # 424761 6-Jan-2011 19:28
Send private message

I should say, it could take 24 hours.

Anyway, Telecom has picked up the DNS now. So all good for now.

I think Telecom really need to brand the error and a link to an article explaining what's going on. It would've saved me hours of time and frustration.

710 posts

Ultimate Geek

Trusted

  # 424771 6-Jan-2011 20:40
Send private message

asianbro: Hi BlakJak,

How would that make a difference? Wouldn't it still take around 24-48 hours for a new DNS to populate?



As a long time ISP geek I find it frustrating when webby types make blanket statements about things they don't actually know about, so please bear with me.

Dns records have a ttl - a time to live. That is, the maximum age of a record that a dns server should cache into memory before it ditches it and goes and looks up the record again. TTL can be set by zone (eg every dns record in the zone has the same TTL) or an individual record can have it's own specified TTL.

If your TTL is for example 8hrs, and I look up your record via my own dns server, my server will cache the answer in memory and for further lookups against my dns server (from me or anyone else) the caches answer will be served - so even if you've made a change since, I won't see it until my caching resolver expires what it has in cache and goes back to your dns server for the record again.

If I know in advance that I will be making changes - say a planned transition of a website from one server to another - I will drop the TTL on the record to something nice and low - say 1 minute - well in advance. This means that the max time where folks out there will be pointed to the wrong place, is only 60s long.

Operating on a low TTL increases the load on your authoritative dns servers, but it does also give you the means to make rapid changes. Sites like trademe dothis in order for them to be able to move load between servers quickly.

If your ISP (the ones to whom you connect) allow the caching resolvers that they operate (ie the dns servers against which you issue requests when surfing the web) to ignore the TTL and hold records for longer than the TTL you have legit cause for complaint. Otherwise dnswill operate as designed, and cache records so that lookup load is shared amongsb clients and the authoritative servers (where the domain is hosted) won't grind to a halt under the strain.

"24-48 hours" is someones attempt to come up wig a generic timeframe within which all changes should reasonnably be seen, this is because 48hrs is typically the longest TTL you will see. The zones I host on my personal DNS have default TTLs between 1 hour and 12 hours.

So create a valid dns entry for the site you're working on but pull the TTL down while in test mode. When satisfied, up the TTL. Job done . (sorry for crusty typing - on my iPhone - what a mission...)




No signature to see here, move along...

 
 
 
 




47 posts

Geek


  # 424808 6-Jan-2011 22:33
Send private message

I did not make any blanket statement. It was genuine question.

I kind of understand what you're saying, but not sure if it is applicable to my scenario. I'll read more about DNS and TTL, thanks for the pointer.

It still stinks that the error isn't branded to cause confusion and wasting time. Also that we can't use local host entries.

BDFL - Memuneh
64980 posts

Uber Geek

Administrator
Trusted
Geekzone
Lifetime subscriber

  # 424823 6-Jan-2011 23:15
Send private message

Put it simply: a well configured DNS will follow the instructions the domain owner puts in the DNS records. The TTL is determined by the domain administrator when configuring the records.

AFAIK Telecom's DNS respect the TTL they find in the records.






47 posts

Geek


  # 424833 6-Jan-2011 23:34
Send private message

So if I set the TTL of mywebsite.com to 1 minute ... then if I add a new subdomain say subdomain1.mywebsite.com, will it get picked up in 1 minute?

BDFL - Memuneh
64980 posts

Uber Geek

Administrator
Trusted
Geekzone
Lifetime subscriber

  # 424834 6-Jan-2011 23:37
Send private message

asianbro: So if I set the TTL of mywebsite.com to 1 minute ... then if I add a new subdomain say subdomain1.mywebsite.com, will it get picked up in 1 minute?


No. If you set TTL of mywebsite.com to 60 seconds it means your DNS will cache the current IP address for 60 seconds, and then the next time you request the address it will contact the authoritative DNS to get the IP address again.

If you add a new subdomain, providing the authoritative server is updated fast then any request will automatically get the new address, since the subdomain didn't exist in any cache before.

 




3506 posts

Uber Geek

Trusted

  # 424840 6-Jan-2011 23:55
Send private message

asianbro: So if I set the TTL of mywebsite.com to 1 minute ... then if I add a new subdomain say subdomain1.mywebsite.com, will it get picked up in 1 minute?


If its a new record and never been queries (and thus cached) before it will work straight away.

As said before, set the TTL really low. While it may have an impact on a production site with more DNS traffic it will be fine for development.

You really should never change your hosts file. 




Speedtest 2019-10-14


Cloud Guru
4060 posts

Uber Geek

Trusted
Snowflake
Subscriber

  # 424842 6-Jan-2011 23:56
Send private message

asianbro: I did not make any blanket statement. It was genuine question.

I kind of understand what you're saying, but not sure if it is applicable to my scenario. I'll read more about DNS and TTL, thanks for the pointer.

It still stinks that the error isn't branded to cause confusion and wasting time. Also that we can't use local host entries.


first, this is not really a "DNS Cache issue".  The problem appears to be that you are being served http via a proxy, and it doesnt see the dns changes yet because you didnt wait long enough to test it (or you didnt manipulate ttls a couple of days ago). 

As for the 'cant use localhost entries' bit - if you buy your own commercial internet connection with dedicated bandwidth then it is probably an option to bypass the proxy. if you want to stick to a contested residential service, then you have to put up with it and its limitations.

The error is:

Network Error (dns_unresolved_hostname)

Your requested host "xyz" could not be resolved by DNS.
For assistance, contact your network support team. 


This is pretty much exactly the error.  the only thing they could potentially add to make it any clearer is a statement that the error occurred at the proxy server.

as a web developer, you should really learn about DNS TTLs and how to manipulate them.  If you ever move a website from one server to another its really something you want to understand as it can really speed up the transition. In addition, you could always use an HTTP trace tool which will likely have shown you that the error was coming from their proxy server.  something like this: http://www.httpwatch.com/download/




Cloud Guru
4060 posts

Uber Geek

Trusted
Snowflake
Subscriber

  # 424844 7-Jan-2011 00:00
Send private message

asianbro: So if I set the TTL of mywebsite.com to 1 minute ... then if I add a new subdomain say subdomain1.mywebsite.com, will it get picked up in 1 minute?


if the TTL was 24 hours before you changed it to 1 minute, then it may be up to 24 hours before all the DNS servers get the new TTL of 60 seconds. so any changes you make will only start turning over in 60 seconds after the existing cached versions expire.

You might also find that some DNS servers will drop TTL to a minimum of 60 minutes, 4 hours etc.  in those cases theres not much you can do






47 posts

Geek


  # 424849 7-Jan-2011 00:25
Send private message

I understand what TTL is ... I thought there's something I didn't know about it when someone here said TTL is my solution, that's why I said I'll read more

Yes new DNS is picked up quick, but I find it's not quick enough. I use local host entry because sometime I need to use my sub domain as soon as I create it (to set it up and test it right away).

With local host entry, it's instant and this had been working fine for a long time until it hit me today.

I wasn't aware of this new cache thing Telecom implemented, so it took me a while to figure out. It would've been less time wasted if there're more clue on the error message.

Local hosts is also useful for quick temporary fix. If a computer somehow can not access a website, sometime it will work with local host entry. Not a good fix, but if you have to use the website, then it will at least allow things to work while proper fix is underway.

 1 | 2 | 3
View this topic in a long page with up to 500 replies per page Create new topic



Switch your broadband provider now - compare prices


Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Samsung Galaxy Fold now available in New Zealand
Posted 6-Dec-2019 00:01


NZ company oDocs awarded US$ 100,000 Dubai World Expo grant
Posted 5-Dec-2019 16:00


New Zealand Rugby Selects AWS-Powered Analytics for Deeper Game Insights
Posted 5-Dec-2019 11:33


IMAGR and Farro bring checkout-less supermarket shopping to New Zealand
Posted 5-Dec-2019 09:07


Wellington Airport becomes first 5G connected airport in the country
Posted 3-Dec-2019 08:42


MetService secures Al Jazeera as a new weather client
Posted 28-Nov-2019 09:40


NZ a top 10 connected nation with stage one of ultra-fast broadband roll-out completed
Posted 24-Nov-2019 14:15


Microsoft Translator understands te reo Māori
Posted 22-Nov-2019 08:46


Chorus to launch Hyperfibre service
Posted 18-Nov-2019 15:00


Microsoft launches first Experience Center worldwide for Asia Pacific in Singapore
Posted 13-Nov-2019 13:08


Disney+ comes to LG Smart TVs
Posted 13-Nov-2019 12:55


Spark launches new wireless broadband "Unplan Metro"
Posted 11-Nov-2019 08:19


Malwarebytes overhauls flagship product with new UI, faster engine and lighter footprint
Posted 6-Nov-2019 11:48


CarbonClick launches into Digital Marketplaces
Posted 6-Nov-2019 11:42


Kordia offers Microsoft Azure Peering Service
Posted 6-Nov-2019 11:41



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.