Hello Folks,

I am in the process of performing an IP renumbering on a couple of servers with several domains.

My aim is to limit propogation time as much as possible. What I think I should be doing is reduicng the TTL to a number closer to 5 or 10 minutes rather than two days, but I would like to get validation before I proceed.

Here is basically what I am doing. Original zone:$ORIGIN com.
domain 86400 IN NS ns2.nameserver.com. ;Cl=2
86400 IN NS ns1.nameserver.com. ;Cl=2
86400 IN SOA ns2.nameserver.com. webmaster.nameserver.com. (
2002031901 10800 3600 604800 86400 ) ;Cl=2
86400 IN A 192.168.0.101 ;Cl=2
86400 IN MX 10 mail.nameserver.com. ;Cl=2
$ORIGIN domain.com.
mail 86400 IN CNAME mail.domain.com. ;Cl=2
* 86400 IN A 192.168.0.101 ;Cl=2Becomes (for 10 minute TTL):
$ORIGIN com.
domain 600 IN NS ns2.nameserver.com. ;Cl=2
600 IN NS ns1.nameserver.com. ;Cl=2
600 IN SOA ns2.nameserver.com. webmaster.nameserver.com. (
2002031901 10800 3600 604800 86400 ) ;Cl=2
600 IN A 192.168.0.101 ;Cl=2
600 IN MX 10 mail.nameserver.com. ;Cl=2
$ORIGIN domain.com.
mail 600 IN CNAME mail.domain.com. ;Cl=2
* 600 IN A 192.168.0.101 ;Cl=2Is this right, or am I completely on the wrong track here?

Thank you much!

Why are you modifying the secondary zone files?

Just put on the first line of your primary zone file:
$TTL 10M

Ahhh, cool, thank you! I didn't realize that would effect all domains.

I think I need a crash course in bind. Thanks for your help, once again taz!

If you have access or the ability to update your current zone files (and/or name servers), you can simply set up all the sites on the new server, which should be running a name service already, and just update the old server's zone's (in that name server) to point to the new IP's (and NS (even if it's the same name)). Once people dial back in or reload (sometimes) or reboot, they'll see the new page/site right away. (Well, assuming your new name server's are all registered and pointing to the correct place -- but you can do that after). That, I have found, provided you use a script to change all the IP's at once (or you can do it manually, but I'd not want to) results in it contacting the new site pretty much for everyone, without waiting the 24 to 48+ hours. Of course, I might have misunderstood your mission here, but the TTL change will be a good bet to add to that mix anyway.

Tim,

Thanks for your response. Fortunately I'm moving sites from one server to another, but I am relocating them to their own private network. The IP's assigned to them right now are not available from where they will be, otherwise I would just add a couple of aliases until propogation occured and be happy. Instead I have to renumber them completely and await propogation, hoping to convince the world to update sooner rather than later.

My motivation for this is two-fold, first the servers will be relocated to their own sub-net and collision domain so all traffic between the servers themselves is not accumulated in my monthly usage. Second, it'll be nice to have such an experience under our belt before we ever do go live and I personally get to learn a bit more about DNS. I've never had much interest in learning it, and without any actual practice it would likely remain a mystery forever. Fun stuff really. I'm amazed both by it's simplicity and it's complexity.

Tim,
If you have access or the ability to update your current zone files (and/or name servers), you can simply set up all the sites on the new server, which should be running a name service already, and just update the old server's zone's (in that name server) to point to the new IP's (and NS (even if it's the same name)). Once people dial back in or reload (sometimes) or reboot, they'll see the new page/site right away. (Well, assuming your new name server's are all registered and pointing to the correct place -- but you can do that after). That, I have found, provided you use a script to change all the IP's at once (or you can do it manually, but I'd not want to) results in it contacting the new site pretty much for everyone, without waiting the 24 to 48+ hours. Of course, I might have misunderstood your mission here, but the TTL change will be a good bet to add to that mix anyway.So ... if we have done this and then all the clients have reloaded and able to see the new website in the new server:
1. What happens when the old server down?
2. What should be done before we can turn-off the old server safely?

Thank you :)

The easy solution for getting this done with minimal downtime is this. Supposing your current TTL in your zones is 86400 then what I would do is change the TTL to something small, like 600 (10 minutes). Then wait at least 86400 seconds (1 day) for everyone who might have cached the old TTL to purge it and get the new 10 minute TTL. Then basically any change to make to your zones from then on should be picked up within 10 minutes by anyone accessing your website making it an almost instantaneous conversion with minimal downtime. Then I'd wait at least a few days and set it back to whatever TTL you were using before.

What about the domain name DNS info? Don't we need to change this first? Or does it matter if it's not being changed?

I guess I'm not quite sure what you're asking. Basically you'd change the TTL in advance, before you need to change the actual DNS info. You really need to understand what the TTL is used for, for this to make any sense.

TTL = Time to live, which is to determine how long the information is kept before it needs to be reload. ... Then basically any change to make to your zones from then on should be picked up within 10 minutes by anyone accessing your website making it an almost instantaneous conversion with minimal downtime. Then I'd wait at least a few days and set it back to whatever TTL you were using before.Sorry if I didn't phrase my question correctly. I assume that what you mentioned above is after the all the accounts have been transferred to the new server. So, if I want to terminate the old server, don't I need to update the domain name dns info?

To make the question make sense, here's a scenario. I have 2 servers, 1 is being used and the other is brand new. The current one (server A:ns1/ns2.california.com) is located in California somewhere, and I want to migrate all the client accounts to the new server (server B: ns1/ns2.florida.com) in Florida with minimum down time. From what I learn from this thread, here's what I get:
1. Copy the client's site to the new server
2. Replace the ns1/ns2.california.com with ns1/ns2.florida.com and put the TTL info for the domain name (i.e. hello.org)
3. Wait 24 hours until everything is propagated

So, before step 2, client computer sees the ns1/ns2.california.com and in about 24 hours, reloads the page and sees ns1/ns2.florida.com (after step 2), right? However, the client domain name (hello.org) nameserver info in the registrar (i.e., Network Solutions) is still pointing at ns1/ns2.california.com.

Now, if I want to turn off ns1/ns2.california.com (current server):
1. Don't I need to modify the domain name (hello.org) nameserver in the registrar database and point it to ns1/ns2.florida.com?
2. Will the client computer goes to ns1/ns2.florida.com directly eventhough the old server is down, meaning that the client can use the cache information directly without accessing the ns info attached to the domain name in the registrar database?

I hope I'm making sense :)

I think I understand what you're asking now. Rather than respond to your example, I'll give you an example of my own on what I would do using the same servers in your example.

Your current DNS servers are ns1.california.com and ns2.california.com and you want to move to different DNS servers with different DNS records.

Change the TTL's of all of your zones right now to something small (like 600). Then wait a day or so for everyone with cached information to purge the old stuff.

Now, anyone who looks up something in your domains will hold it for a maximum of 10 minutes.

Set up your hosting accounts on the new web server properly.

Change all of the DNS entries on ns1 and ns2.california.com to point to the new web server IP addresses. Copy all of the DNS zones over to the new DNS servers, having identical zones on both servers.

Submit the new DNS servers to Network Solutions (or whoever you registered the domains with). After you're satisfied the change has been made in their database pointing everything to ns1 and ns2.florida.com then remove all the old zone info from ns1 and ns2.california.com

Done.

The advantage to doing this is that after you've made the changes, everyone should pick them up right away and nobody should be querying the old web servers. So after you've changed the DNS entries you should be able to remove the web sites from the old server immediately instead of having to wait 24 hours for everyone's DNS server to purge the old info from it's cache.

BillyJoe,

Thank you very much for your advice :)

Grateful,

No problem. This is actually not all that beneficial if you're able to keep both the old and new web and DNS servers functioning during the transition. Where this becomes really useful is when you need to do something like changing IP addresses of your DNS servers and/or web servers, because the new addresses would be functional and the old addresses wouldn't.

Hehe... Heya Scott,

I am shocked you didn't ask me for help on this before you posted here. Quite a surprise to see you posting on Web Hosting Talk. I only recently have come across this. BTW, Scott, it is me, Brandon, from DCO.

Earlier you said something about wanting to learn more about DNS. I would recomend the ORA books for that.

For now, if you want any reverse DNS for your IP's, you can always fire it off to me in an E-Mail. TTFN :D

Hey Brandon,

Thanks for the book recommendations, I'll check em out. Honestly, I'm not sure why I didn't think to ask you guys for help on the DNS setup. Though after our conversations when we installed the router and such I think I'll likely be picking your brains quite often when I have similar problems to solve.

Thanks for your help!

Pick Away... Pick Away! How are things going, you guys almost ready to go live? Hspher working good? No problems with the boxes that are downstairs? :confused:

We are live now believe it or not. Cautiously so since we're really waiting for the H-Sphere 2.1 release to start promoting this end of our business.

BTW, thanks for making the renumbering go so easily. It's nice to have plenty of room to grow with no containment. I'm thinking of bringing a new PowerEdge 1650 out there in a month or so to add to the mix.