>We have an Imail server that resides on a T1 network with the ip
>address of 38.193.29.7 we are wanting to move the Imail server to a
>different T1 network with the ip address 66.65.8.1, but keep the
>same host name. We are also going to have to move the DNS records
>to a different server on the 66.65.8.* We are wanting to do this
>with no downtime.
What you do is reduce your TTL on all your zones to 1 hour. No need
to go to 15 minutes since most DNS servers (and 80% of Internet is
BIND) only purge their cache every 60 minutes. So if you set your
TTL to 1 minute (dumb), your records will not be purged from most DNS
for an average of 30 minutes (1/2 of 60).
> If I change the information with network solutions to have the DNS
> point to the 66.65.8.* what about the people that send mail to the hosts?
For a max of one hour (ie, nothing to sweat about), they could obtain
the cached MX/A record for the old ip, try to send to it, fail, and
try again later. Probably they will keep trying for 24 hours
minimum, during which time when they do an MX query, they will get
the new MX and A record and the mail will go through.
>How can I move the domain without any interuption? Is there anyway
>to have the old DNS provider point to the new DNS server kind of
>like a forward?
yes, of course. No forwarding, but as soon as your mail server is
running at the new ip, the existing DNS can/should point MX and A to
the new ip.
So the most important tactic is to reduce the TTL on all your domains
to 1 hour. After the switch, move the TTL back to 1 day. Due to the
queue lifetimes for most mail servers, you probably won't lose any mail.
look at this:
# dig @a.gtld-servers.com ipswitch.com ns
; <<>> DiG 8.3 <<>> @a.gtld-servers.com ipswitch.com ns
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2
;; QUERY SECTION:
;; ipswitch.com, type = NS, class = IN
;; ANSWER SECTION:
ipswitch.com. 2D IN NS ALPHA.ipswitch.com.
ipswitch.com. 2D IN NS HUB.ipswitch.com.
;; ADDITIONAL SECTION:
ALPHA.ipswitch.com. 2D IN A 216.104.149.100
HUB.ipswitch.com. 2D IN A 156.21.1.2
The gTLD servers have a standard 2 day TTL on all glue records. You
can't change that. From the point when you change your NS ip's with
the roots, your previous glue records will be cached by DNS servers
for up to 2 days. Can't do nothing about that.
Len
http://MenAndMice.com/DNS-training : In Austin, TX; SFO, CA; Paris,
FR
http://BIND8NT.MEIway.com : ISC BIND 8.2.3 "NT3" for NT4 & W2K
http://IMGate.MEIway.com : Build free, hi-perf, anti-abuse mail gateways
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