IP changed overnight

can apache help

[smiddy]

I checked my stuff out this morning and nothing was working. Turns out my cable company changed my ip address over night. Not sure why as it's never happened before.

So I went to register.com to change the ip to the new one. Am I down until this change takes effect or is there a way to redirect?

The site I have is a hobby, not business. So I host it myself through my cable company.

[zCat]

If you have access to the original IP you could set up some kind of redirect. As this is not the case, all you can do really is wait until the DNS changes work through.

To prevent this happening again, find out if your domain registrar offers a facility for your IP address to be automatically updated by a script running on your computer.

Note: it's possible your own local system might have the old IP address cached somewhere, which means you might not be able to access your own server via the domain name, but others can.

[smiddy]

Thanks for the reply.

The site is not accessible from outside. I use Citrix to get into my office where I can test external access...no dice.

How can I test to see when the DNS change has been made? Is it usually a full 24 hours? I'm really p*ssed because I've been waiting for that Google spider and I'll bet I missed it. Murphy's Law and all.

[RonPK]

> How can I test to see when the DNS change has been made?

The change is made immediately. The question is when ISPs pick up the changes. Some are fast, others are slower. 48 hours should be the max...

[smiddy]

When you say ISP's, do you mean when the isp I use picks it up? Or are you saying that all isp's need to pick it up. So, some users can get in and others can't as time goes along?

[sitz]

The time it will take will depend on how your DNS provider has your zone configured; there's a TTL (time-to-live) value configured in the zone file (and sometimes per A record), and it can, in theory, be anything. It's *generally* somewhere between 18 and 36 hours, though.

If you want to find out what it is, you'll need to know which nameservers are authoritative for your zone; this will be the IP addresses in the 'NS' lines of your zonefile (they're *probably* the nameservers that appear in your 'whois' data, but there's no guarantee of that).

If your nameserver is ns1.exampleisp.com and your domain is example.com, then run the following:

$ dig @ns1.exampleisp.com www.example.com

; <<>> DiG 9.2.3 <<>> @ns1.example.com www.example.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64592
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 1

;; QUESTION SECTION:
;www.example.com. IN A

;; ANSWER SECTION:
www.example.com. 86400 IN A 192.168.1.100

[other data snipped]

A little cryptic, but it boils down to this:

you sent a query to ns1.example.com for www.example.com

'www.example.com' is the 'question'; you're asking for information about it; specifically, you're asking for the 'A' record (which maps the hostname to an IP)

'www.example.com' is subject of the 'answer'; the server is saying "I have information about www.example.com"

www.example.com currently points to 192.168.1.100

the TTL on that record is 86400 seconds (24 hours)

Hope this helps. =)

[smiddy]

Is that all run from a command prompt? It's a little confusing to me but I'd like to give it a go.

[RonPK]

Thx for the authoritative answer, sitz ;)

[smiddy]

Here's what I came up with...

www.mysite.com. 21600 IN CNAME mysite.com.
mysite.com. 21600 IN NS dns20.register.com.
mysite.com. 21600 IN NS dns19.register.com.

So is this telling me I should be up 6 hours from my change?

[jdMorgan]

Yes, six hours minimum, or up to twelve hours if an ISP grabbed the old IP address translation just the second before you changed it.

Hosting a web site on a dynamic-IP home line is a bad idea for a couple of reasons. First, it usually against the terms of service of the ISP (and for good technical reasons, not just that they are unreasonable). And second, because you'll need a service like dyndns to handle DNS for it, which raises cost and complexity.

Jim