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Moved From Johnny To Tommy -- 404/500 Errors


Korejora

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Hello. I recently moved servers from Johnny to Tommy (by deleted account at this script and then signup to make a new account). Previously on Stevie the domain worked, and then when I changed to Johnny in March, it continued to work without any new configuration. But, now that it is changed to Tommy, the domain doesn't work.

 

- The domain leafbubble.ca has nameservers ns1.heliohost.org and ns2.heliohost.org set up.

- I can access the cpanel just fine at https://tommy.heliohost.org/ and put files in the public_html

- leafbubble.ca/ and any subdirectories give a 404 error, although there is index.html there, and leafbubble.ca/cpanel gives a 500 error.

- the username for the account is "kore" (different from the forum account).

 

Do I need to change more of the configuration? Sorry if this is insufficient information. Please tell me if you need anything else.

(Also, is there a way I can view the html without using that domain, if it cannot work?)

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The domain leafbubble.ca has nameservers ns1.heliohost.org and ns2.heliohost.org set up.

-

after a edit of this post to use the correct domain [ http://leafbubble.ca/ ] - I 'see'...

 

<html>

<head>

<style>

body

 

{

 

color: darkblue;

background-color: lightblue;

}

</style>

</head>

<body>

 

TEST_STRING_4541589465282432892

 

</body>

</html>

 

###

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Hmm... Clearing the cache was already required to get the 404 in the first place, because it was loading previously cached files from when it was on Johnny. I also tried a different browser.

 

I have tried loading it again after simply waiting a few hours, and it now connects and displays what bdistler described. The FTP server also works where it did not work before. It is a mystery.

 

Thank you for looking into it. Sorry for wasting your time.

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However, why is it displaying the html instead of rendering it? Have I entered the file incorrectly?

-

this is the source-code my browser shows...

<html>
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8">
	<title></title>
</head>
<body>
<p><html><br />
<head><br />
<style><br />
body</p>

<p>{</p>

<p>    color: darkblue;<br />
    background-color: lightblue;<br />
}<br />
</style><br />
</head><br />
<body></p>

<p>TEST_STRING_4541589465282432892</p>

<p></body><br />
</html></p>

<p></p>
</body>
</html>

and that source-code will make the page showing HTML code

###

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The FTP server also works where it did not work before. It is a mystery.

It's not a mystery. It's called DNS caching. When you type in a human readable domain name like leafbubble.ca the first thing your browser does is try to convert that into a machine-usable number. To reduce load on the DNS servers this number is cached in your computer, and in your router, and in the nearby routers of your isp too. The reason caching is a good idea is because this number rarely changes for most sites. The TTL record of a domain which stands for Time To Live instructs the various places DNS IPs can get cached the maximum length they can hold that value for before they're required to contact the authoritative dns servers to make sure the value hadn't changed.

 

tl;dr: Your computer still thought your domain was on Johnny because it hadn't bothered to check to see if it had moved.

 

Thank you for looking into it. Sorry for wasting your time.

It's not a waste of time. Heliohost is for learning and it's wonderful when people ask great questions like you are and maybe learn how this all works.
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Krydos, on 04 May 2017 - 10:03 PM, said:

It's not a mystery. It's called DNS caching. When you type in a human readable domain name like leafbubble.ca the first thing your browser does is try to convert that into a machine-usable number. To reduce load on the DNS servers this number is cached in your computer, and in your router, and in the nearby routers of your isp too. The reason caching is a good idea is because this number rarely changes for most sites. The TTL record of a domain which stands for Time To Live instructs the various places DNS IPs can get cached the maximum length they can hold that value for before they're required to contact the authoritative dns servers to make sure the value hadn't changed.

It also caches to the router? This cache is different from a navigator/browser cache? Does that mean that e.g. a different computer connected to the same router would also have that domain name cached?

 

I am trying to read about this on Wikipedia Name_server#Caching_name_server but it is still a bit unclear to me. From googling, it seems like to clear it (on Windows) you run ipconfig /flushdns. Is this correct? (For Ubuntu it's a bit more involved.)

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From googling, it seems like to clear it (on Windows) you run ipconfig /flushdns. Is this correct? (For Ubuntu it's a bit more involved.)

Correct. That command makes windows forget all the looked up addresses in its cache. If you run that, the next time you visit the domain, it will have to ask a DNS server instead (typically one run by your ISP unless you've changed your settings manually).

 

A DNS server can either be the one that holds the records about the domain (the "authoritative" server), have the answer cached already from previous lookup, or look up another server that might know and pass on the request. Eventually it'll reach the authoritative server and get the address it needs.

 

A complete look up from end to end for domain.com would be something like this. In reality, these servers will have caches of their own and may not actually need to ask the next one in line because they remember from before (this was your problem...either your PC or the servers remembered from before, not realizing the answer had changed in the meantime). The below is simplified quite a bit, but explains the general process.

  • PC checks if its cached. If yes, use the data in the cache.
  • PC asks the configured DNS server to for information for domain.com
  • DNS server doesn't know where it is, so it starts working down the chain, starting with ".", also known as root. This is to the right of the .com, but that period is generally not written. The internet root servers are asked where the servers for ".com" are (most servers will generally have such information already and not actually need to ask the root servers).
  • DNS server then asks the servers for ".com" (of which there are VERY many) where domain is.
    • The ".com" DNS servers return NS records pointed to ns1.heliohost.org and ns2.heliohost.org. NS records basically say "these servers are the ones responsible for the answer for domain.com. Ask them."
    • If an A record was found here instead of the NS records, the IP listed in the A record would be returned as the answer and the lookup would be complete.
    • This step is one of the reasons you have to wait for DNS propagation when you change your nameservers. Because there's many DNS servers that handle answers for stuff under .com, they all need to know the answer to this question. Lookups can fail if you get one that hasn't been informed of the answer yet.
  • Assuming an NS record was returned, ask the name servers listed, and they respond with an IP for domain.com. The response is passed back to your PC.
  • PC connects to the IP given and asks for content.
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