>We are moving our entire domain and all to new servers with new IP address..
"renumbering", are we?
>I have an idea on how this works but just to make sure.. How long does the
>IP changes to the FQDN usually take across the board? I believe the TTL is
>2 days on our end but I am not sure this is how it works for all how happen
>to query our DNS.
Don't just believe it, know it:
# dig @root.californian.net bakersfield.com ns
; <<>> DiG 8.2 <<>> @root.californian.net bakersfield.com ns
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 3
;; QUERY SECTION:
;; bakersfield.com, type = NS, class = IN
;; ANSWER SECTION:
bakersfield.com. 1H IN NS root.californian.net.
bakersfield.com. 1H IN NS realserver.californian.net.
So your current TTL is 1H
so if all your zones are at 1H, there's nothing to do, but if they
are 2D or 3D, then 2D or 3D before the renumbering event, reduce all TTL to 1H.
Also note the TTL's for yr NS's in the root-servers.net:
dig @a.root-servers.net bakersfield.com
; <<>> DiG 8.2 <<>> @a.root-servers.net bakersfield.com
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
;; QUERY SECTION:
;; bakersfield.com, type = A, class = IN
;; AUTHORITY SECTION:
bakersfield.com. 2D IN NS ROOT.CALIFORNIAN.NET.
bakersfield.com. 2D IN NS REALSERVER.CALIFORNIAN.NET.
These last two lines in the "additional section" are the "glue
records" that point Internet to your DNS's ip's. Note that they have
a TTL of 2D, which is standard root TTL, NOT the 1H you have in your
zone files.
So at "2D" before you do the switch, make sure all the TTL of all
your domains is 1H. Your DNS's will get hammered at lot more due to
the short caching.
Wait 2D until all the records expire in the caching DNS's in Internet.
background: when Internet is querying for the zone data of
bakersfield.net, a DNS (that doesn't have the cached locally) asks
the roots for the DNS for bakersfield.net and gets back the A records
for your HOST/DNS servers. Then that DNS queries your DNS's at those
ip's for the zone data of bakersfield.net.
The pivot in your renumebering project is when the root-servers.net
get updated with the new ip addresses for your HOST (DNS) glue records.
Therefore, your pivotal action is sumbitting the HOST A record
modifications to your registrar. If all goes well there, your
registrar sends the changes to Net Sol and the next morning when Net
Sol updates the root servers, the pivot pivots. Subsequent queries
to roots for NS's of bakersfield.net will now result in new ip's of your DNS's.
Then don't forget to modify your zone files back up to TTL of 1H.
Len
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