How a Domain is like a Writing Desk - Domain Names, 404, DNS & ARecordsNext Post
Today I'm going to discuss Domain names in a very top level way that i hope all our readers will be able to appreciate. Domain names and hosting are still not well understood by the general public and that's because there are a lot of technicalities that you come to a company like us for.
The analogy I like to use if that of the postal system, while not totally accurate it does help give you a real world framework we are all familiar with.
Domain - P.O.BOX
When you buy a domain name it's a bit like a P.O.BOX... It's pretty meaningless until you point it at something and when someone delivers letters to it the postman knows where to deliver it too.
Think of your domain (e.g. www.comgem.com) as a P.O. BOX and your hosting as a physical building where letters sent to the P.O.BOX are directed to arrive. Should you change buildings/domains you don't want to lose the address all your contacts know you by so you simply redirect the P.O.Box to the new building.
Hosting - Physical Building
Hosting is like the physical building. You can have the site hosted on a server and when someone wants to see a page from your site they type in the page they want and the domain name directs them to the hosting where the appropriate page is kept and it's delivered back to you. It's just like addressing a letter to a department in an office building and them replying back to you... the physical address of the building doesn't matter as long as the letter gets to it correctly and find the right person/department to get a reply.
Domain Name Server (DNS) - Post Office
To keep track of all these addresses and hosting the web uses DNS servers to keep track of the massive amounts of information in a decentralised way. The DNS is like a local post office (local to the letter writer/site visitor) that checks the address typed and directs you accordingly.
This is fine when nothing changes but when you do change your domain it takes time for all the DNS around the world to take note. It's like moving buildings and telling the post office you've moved.. it takes a little while for change to get actioned and for a short while mail gets delivered to the old address before it's directed to the new one.
404 - Return to Sender
Trouble can happen if you send a letter to the right building but the department doesn't exist.. In this case the department is analogous to a page on your site.
Say when you delete a page, the visitor types in the wrong name or you redevelop a site; the exact page name might no longer exist. In these cases the 404 page is returned to say that you got to to the site but we couldn't find the page. Some 404's will give helpful or funny advice but the main thing is the visitor sees a friendly page showing them the site is ok.. it's just the specific item they were looking for is unavailable.
301 Redirect - Forwarding Mail
To combat the above, when you redevelop a site and lots of pages your customers commonly use have changed you can set-up 301 redirects to forward visitors who land on specific missing pages to more useful ones (e.g. .com/search.php no longer exists the 301 can be set-up to redirect to the new .com/searching.asp page and the 404 need not be shown and the customer got the right page first time).
Note that this can be helpful with search engines too as in the days after going live with a new site the search engine will be out of date until it re-crawls your site and will for a time direct people to those non-existent pages.
Updating your Domain Name
When you move hosting you need to update your domains Arecord to the new hosting address, all you need is:
- an IP number (4 sets of digits separated by fullstops e.g. 000.000.000.000) which is the address of your hosting.
- update your domain's ARecord which is used to point to that IP Number.
We'll provide you with your personal IP Number and you will need to follow these general steps:
- Login to the site you used to purchase your domain name
- Locate the registry services
- Locate the ARecord or AName section
- Edit the AName section
- Type in your IP number exactly as it appears in our email to you
Be very careful when setting an IP as even a single digit mistake can point you at a completely different site.
Propagation & DNS
Officially most DNS say 24-48 hours is the propagation period for a domain update, during which time some people will see the new hosting while others will still see the where the domain was pointed at previously, however typically DNS close by (within the same country as you) update within a matter of minutes while countries further away typically take around 1 hour and you should be worldwide for most people within 2 hours.
By Alanna at 1 Sep 2014, 10:12 AM