W W What's up doc?

August 3, 2007 11:15 AM

I need to know a lot more about domain name hosting than I do right now.

Earlier this week our web host told me that they were moving our site to another server and we would have to have the domain point to that new server. The actual domain names are held with a different company from the web host.
So my workmate has to ask the domain hosting person guy in our company to contact the domain hosts to repoint the domain name to the new IP. (still with me?).
He asks in the format "please change domain zingdomain.com to point to new IP". He gets a reply "the A names have been changed"
Two days later the domain starts resolving on zingdomain.com, but with an error when you use www.zingdomain.com. We discover the www domain name has not been repointed, but the non www has, so we have to go back to our guy and ask that the www name be also done (the web host tells us this).
OK so the question is, WTF is happening here?
1. Do you always need to specify for www and non www variations?
2. Why is nobody saying something like "do you want the www's done too?" when we ask for changes?
3. Does it always take at least 2 days for IP changes to resolve?
I know little about this stuff and am at the mercy of our host, our network guy etc. Please help me understand more and fuck up less.
We are going to be farming all this out soon, but in the meantime have to live with the situation as is.

posted by zingzangzung to computers & internet (6 comments total)

1. It sounds like your DNS entries are set up so that 'mydomain.com' and 'www.mydomain.com' are both A name entries. If you know that 'www.mydomain.com' is always going to point to the same place as 'mydomain.com', you should ask your DNS admin to change the entry for 'www.mydomain.com' from an A name to a CNAME that points to 'mydomain.com'. That way, whenever 'mydomain.com' changes IP address, this will be automatically reflected for 'www.mydomain.com'.

2. Your DNS admins aren't terribly on the ball, it sounds like.

3. DNS update propagation times are based on the cache settings on the DNS server where a particular client machine (i.e. your web browser machine) gets its name service. If your client machines are getting their DNS service from these servers where the changes are being made, you should ask your DNS admin additionally to flush the DNS cache for your DNS entries, once they've made the updates. This should make the changes pretty much instantaneous, for the clients who get their DNS service directly from that DNS server.
posted by Brak at 11:37 AM on August 3, 2007

To get you started, the "zingdomain.com" is considered your top-level domain. All things (like the www) preceding it are considered sub-domains. So www.zingdomain.com, JoeMamma.zingdomain.com, etc.zindomain.com would all be sub-domains of zingdomain.com.

Here's a great Wikipedia page to start with on how the DNS system works. It goes into the architecture, lookups, caching (why you see it take a couple days to work), and the different types of records (A record, CNAME, etc). So I'd start by reading that, and other linked pages (nameservers, hostname, etc) from that Wikipedia page. Hopefully that'll give you enough of a foundation in the inner workings and terminology so you can do other meaningful searches and find what you're looking for by using the right words.

And I sympathize with you and the "laziness" of the domain hosting guy. I think he should have taken the time to ask more questions on what you were really looking for, because chances are you came across as not knowing what you really needed since you didn't know all the terminology. Maybe it might help to mention that you're totally new at this and may not necessarily think of everything so you'll need their help considering what other things that need to be updated. Honestly, reading that Wikipedia page and learning some of the terminology will probably make things worse because the support person may assume you know it all when you might not.
posted by JibberJabber at 11:40 AM on August 3, 2007

The web host can surely also do the DNS hosting for you. That would hopefully eliminate this problem in the future (this does not require you to change domain registration providers, but I'll bet that the web host can do that too).
posted by winston at 11:58 AM on August 3, 2007

1. Do you always need to specify for www and non www variations?

Yes, unless you're using a wildcard DNS, which you probably want. (ie, anything_here.yourdomain.com will redirect to your domain).

2. Why is nobody saying something like "do you want the www's done too?" when we ask for changes?

Bad technician.

3. Does it always take at least 2 days for IP changes to resolve?

That's the time most places quote, but these days, most changes seem to go through in a couple hours. You can usually refresh *your* local cache using 'ipconfig /flushdns ' from the command line on a windows box, although this isn't gonna to force whoever you're using for DNS to refresh theirs.
posted by fishfucker at 12:57 PM on August 3, 2007

Here are the things that might alleviate your confusion:

1. foo.com is a domain. Let's say it is an A record pointing at 1.2.3.4.

2. www.foo.com is a subdomain of foo.com. It should likely be a CNAME pointing to foo.com, although it could also be an A record pointing at 1.2.3.4 or an A record pointing at some other IP or a CNAME pointing at some other domain.

3. The turnaround time for updates adds up in a couple of places...

- the provider may only launch updates to production every hour, or every day, or as soon as they're done -- but they might "do" them in a batch every week. So there's a provider delay.

- the TTL (time to live) on the records has to expire for the record to fully propogate. Set your TTLs to an hour, and within an hour all *well-behaved* systems have gotten a fresh lookup -- but some (Comcast, I'm looking at you) may ignore the TTL and sit on the record for a week or more, so YMMV.

It's always best to transfer such that you keep the old AND new systems alive for a longer period of time than seems necessary, and verify that traffic has stopped arriving at the old location before shutting it off.
posted by davejay at 2:54 PM on August 3, 2007

for pedantics, set the TTL to an hour on the old record sufficiently in advance for all systems to pick up the shorter TTL, then make the change, and your change will propogate (mostly) within that hour.
posted by davejay at 2:55 PM on August 3, 2007