Wednesday, August 01, 2007

Use A CNAME Referral For Custom Domain Server Reference

Have you ever been in line at the bank, or the post office, waiting patiently access to the "next available cashier"?

Probably a lot, if you're like me. Have you ever watched someone stroll through the door, around the line, and walk up to the nearest cashier, occupied or not, and demand service now? Have you ever ended up just behind that person who just crashed the line? Have you ever been that person who just crashed the line?

Have you ever seen the line come to a screeching halt, while the manager tries to convince the line crasher to get back into the line, and wait politely to be served? Not fun for anyone, that scene. Nobody accomplishes much, while everybody calms down.

The load balancing server array "ghs.google.com" is similar to the line in the bank.

With your custom domain setup to use a CNAME referral to "ghs.google.com", each reader of your blog is uniformly and efficiently issued the IP address of the "next available BlogSpot server". There are thousands of BlogSpot servers, and the load (the readers of millions of Blogger blogs) is evenly spread across the entire array.

On the other hand, if your custom domain is forwarded to "xxxxxxxx.blogspot.com" (the BlogSpot address of your blog), each reader of your blog does a normal DNS lookup - and probably uses a cached IP address in getting a BlogSpot server.

If an IP address is in cache, it's likely that it's pointing to a server that's busy (how did the address get into cache after all?). Your readers will be competing with readers of other blogs, for server access. That's like the idiot who just crashed the line, nobody wins - everybody loses time and patience.

Similarly, blogs published to domain addresses which use an "A" referral to the alias array ("216.239.nn.21") will be a problem - for themselves and for others.

In an alternate scenario, the line crasher will walk up to an unoccupied cashier, who is just closing down and heading out to lunch. The line crasher stands in front of the cashier, who simply puts the "Out To Lunch" sign in place, and walks away, leaving the line crasher unattended, and with no place in line.

If the domain is forwarded (or if you have "A" or "CNAME" records to one or more fixed IP addresses) to server(s) that just went down, your reader gets a 404 - Server Not Found (not responding). This is a scenario being experienced by quite a few bloggers, starting 17 September 2007, and periodically by more bloggers.


Surely, the entire domain isn't down. No, most likely, the server.

A load balancing server (like a "next available cashier" line) assures that you always get a working server (not a cashier on the way to lunch).




I haven't changed anything!! It just stopped working on its own!!!



When you setup a CNAME referral to "ghs.google.com", Blogger provides an IP address of a server, at that moment in time, that's both
  1. Online.
  2. Available.
That's the job of a load balancing server.

When you setup a fixed IP address (using either an "A" or "CNAME"), and your readers use the same IP address (or one of a few) every time, that server may be either
  1. Offline.
  2. Assigned by ghs.google.com to someone else, and busy.
Now your readers are interfering with the job of ghs.google.com, and with other bloggers who waited in line, patiently.

For Blogger to work properly, everybody has to wait in line, and go to ghs.google.com, for a server assignment. There are thousands of servers at Google - at any time, any number might be offline. The load balancing host ghs.google.com dynamically assigns your reader a server that's available, if your blog DNS is properly setup to convince your reader's browser to ask for an available address.

If your blog bypasses load balancing, you cause two possible problems.
  • If your designated server is down, your reader gets a 404 error, and no access to your blog.
  • If your designated server is busy, your reader bypasses load balancing, and overloads it. The other users of that server get poor response, along with your readers.
In either case, nobody wins.

Why treat your readers like line crashers? Let your readers play by the rules, just like everybody else. Use "CNAME" referral to "ghs.google.com" - let "ghs.google.com" assign the "next available server", and let everybody access your blog politely. If your DNS host doesn't support "CNAME" referrals (not all do, for some reason), find another DNS host that does.

You may, depending upon your need and current availability of Google servers, chose any one of three reliable DNS configurations.

Don't try to make up your own solution - and if you do try your own solution, don't be surprised by the results.

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9 comments:

Spartan said...

Your article was very helpful. CNAME settings have been a headache for me for quiet some time now. I was wondering if you could tell what are the CNAME settings I need to provide my domain registrar for my blog at blogger.com
is this right :
[www.].my_domain.com that points to ghs.google.com

Chuck said...

Base the CNAME upon the published blog URL.
1) Add the DNS:
www.my_domain.com. CNAME ghs.google.com.
(see the extra periods ("com.")?
2) Publish the blog to www.my_domain.com (no "com." there)!!

Be precise with the CNAME record!

la fourchette said...

oh my goodness! i'm so lost here. i've tried since november to get my blogspot blog to go to my custom name (which i purchased through google...so i thought it would be easier.) i've crawled over many, many directions and followed them only to continue to come up with...absolutely nothing!
help!
in my domain services page, the dns information is set to default. the host records section is where i think i've created some havoc. currently there are 3 numerical addresses preceded by @ in the host name window bars. following that, i've taken out (oops!) the calendar/docs/mail/start/ addresses and have now two cname addresses: www.chezlafourchette.com. and another without the www. both are set to the ghs.google.com. yes, with that extra point at the end of each - which then erases my two cname addresses and gives me an error message saying: Host name cannot end with a period (.)

it allows the addresses to be registered without those points...but no pinging happening...

i'm just not sure what i'm doing incorrectly here...and until i get it set up on the host gig, the blogspot will not redirect.

help! any suggestions will be greatly appreciated!

thanks in advance...for anything!
leslie

Chuck said...

Leslie,

Your problems really need to be explored, interactively, in forum help. Do you have an open thread there yet? If not, please start one. If you do, what Subject did you use? Be precise please.
Google Blogger Help - Broken

Media Blogger said...

Do you know what the TTL should be set to when creating a CNAME record?

I put the domain as "ghs.google.com" and it automatically had "14400" under the TTL - is this right?

I've waited for about a week and nothing has happened.

Shitu said...

thanks man it actually works....

Sushil Kumar Gupta said...

How can i use my registered domain sushilgupta.com.np to my existing blog, onlineinfopoint.blogspot.com . For the settings in my registrar website, there asks the primary & secondary host name and i.p. address, to provide there?

Chuck said...

Sushil,

This would be a good topic for GBH: How Do I?, or Nitecruzr Dot Net - Blogging, I think. The online forums are much easier to use, then Blogger Blog Commenting, for interactive problem solving.

Chris said...

Thank you for clearing some of the doubts that most of the people tend to have about domain services, thank you for the help, really appreciate the hard work!
Cheers!
Chris